diff --git a/framework/src/Volo.Abp.AspNetCore.Components.MauiBlazor/Volo/Abp/AspNetCore/Components/MauiBlazor/MauiBlazorRemoteTenantStore.cs b/framework/src/Volo.Abp.AspNetCore.Components.MauiBlazor/Volo/Abp/AspNetCore/Components/MauiBlazor/MauiBlazorRemoteTenantStore.cs
index 235fe74354..d17a2b6f87 100644
--- a/framework/src/Volo.Abp.AspNetCore.Components.MauiBlazor/Volo/Abp/AspNetCore/Components/MauiBlazor/MauiBlazorRemoteTenantStore.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Components.MauiBlazor/Volo/Abp/AspNetCore/Components/MauiBlazor/MauiBlazorRemoteTenantStore.cs
@@ -98,7 +98,7 @@ public class MauiBlazorRemoteTenantStore : ITenantStore, ITransientDependency
             return null;
         }
 
-        return new TenantConfiguration(tenantResultDto.TenantId.Value, tenantResultDto.Name);
+        return new TenantConfiguration(tenantResultDto.TenantId.Value, tenantResultDto.Name!);
     }
 
     protected virtual string CreateCacheKey(string tenantName)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo.Abp.AspNetCore.Mvc.Client.Common.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo.Abp.AspNetCore.Mvc.Client.Common.csproj
index 9f9ddb9755..49c0eca552 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo.Abp.AspNetCore.Mvc.Client.Common.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo.Abp.AspNetCore.Mvc.Client.Common.csproj
@@ -5,6 +5,8 @@
 
     <PropertyGroup>
         <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+        <Nullable>enable</Nullable>
+        <WarningsAsErrors>Nullable</WarningsAsErrors>
         <AssemblyName>Volo.Abp.AspNetCore.Mvc.Client.Common</AssemblyName>
         <PackageId>Volo.Abp.AspNetCore.Mvc.Client.Common</PackageId>
         <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteExternalLocalizationStore.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteExternalLocalizationStore.cs
index c5548acc62..4de2f28391 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteExternalLocalizationStore.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteExternalLocalizationStore.cs
@@ -22,13 +22,13 @@ public class RemoteExternalLocalizationStore : IExternalLocalizationStore, ITran
         LocalizationOptions = localizationOptions.Value;
     }
     
-    public virtual LocalizationResourceBase GetResourceOrNull(string resourceName)
+    public virtual LocalizationResourceBase? GetResourceOrNull(string resourceName)
     {
         var configurationDto = ConfigurationClient.Get();
         return CreateLocalizationResourceFromConfigurationOrNull(resourceName, configurationDto);
     }
 
-    public virtual async Task<LocalizationResourceBase> GetResourceOrNullAsync(string resourceName)
+    public virtual async Task<LocalizationResourceBase?> GetResourceOrNullAsync(string resourceName)
     {
         var configurationDto = await ConfigurationClient.GetAsync();
         return CreateLocalizationResourceFromConfigurationOrNull(resourceName, configurationDto);
@@ -63,7 +63,7 @@ public class RemoteExternalLocalizationStore : IExternalLocalizationStore, ITran
         return resources.ToArray();
     }
     
-    protected virtual LocalizationResourceBase CreateLocalizationResourceFromConfigurationOrNull(
+    protected virtual LocalizationResourceBase? CreateLocalizationResourceFromConfigurationOrNull(
         string resourceName,
         ApplicationConfigurationDto configurationDto)
     {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteFeatureChecker.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteFeatureChecker.cs
index d3969e7888..f356324445 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteFeatureChecker.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteFeatureChecker.cs
@@ -13,7 +13,7 @@ public class RemoteFeatureChecker : FeatureCheckerBase
         ConfigurationClient = configurationClient;
     }
 
-    public override async Task<string> GetOrNullAsync(string name)
+    public override async Task<string?> GetOrNullAsync(string name)
     {
         var configuration = await ConfigurationClient.GetAsync();
         return configuration.Features.Values.GetOrDefault(name);
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteLocalizationContributor.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteLocalizationContributor.cs
index e6e180c5f2..c361186a75 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteLocalizationContributor.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteLocalizationContributor.cs
@@ -14,9 +14,9 @@ public class RemoteLocalizationContributor : ILocalizationResourceContributor
 {
     public bool IsDynamic => true;
 
-    private LocalizationResourceBase _resource;
-    private ICachedApplicationConfigurationClient _applicationConfigurationClient;
-    private ILogger<RemoteLocalizationContributor> _logger;
+    private LocalizationResourceBase _resource = default!;
+    private ICachedApplicationConfigurationClient _applicationConfigurationClient = default!;
+    private ILogger<RemoteLocalizationContributor> _logger = default!;
 
     public void Initialize(LocalizationResourceInitializationContext context)
     {
@@ -26,7 +26,7 @@ public class RemoteLocalizationContributor : ILocalizationResourceContributor
                   ?? NullLogger<RemoteLocalizationContributor>.Instance;
     }
 
-    public virtual LocalizedString GetOrNull(string cultureName, string name)
+    public virtual LocalizedString? GetOrNull(string cultureName, string name)
     {
         /* cultureName is not used because remote localization can only
          * be done in the current culture. */
@@ -34,7 +34,7 @@ public class RemoteLocalizationContributor : ILocalizationResourceContributor
         return GetOrNullInternal(_resource.ResourceName, name);
     }
     
-    protected virtual LocalizedString GetOrNullInternal(string resourceName, string name)
+    protected virtual LocalizedString? GetOrNullInternal(string resourceName, string name)
     {
         var resource = GetResourceOrNull(resourceName);
         if (resource == null)
@@ -50,7 +50,7 @@ public class RemoteLocalizationContributor : ILocalizationResourceContributor
 
         foreach (var baseResource in resource.BaseResources)
         {
-            value = GetOrNullInternal(baseResource, name);
+            value = GetOrNullInternal(baseResource, name)?.ToString();
             if (value != null)
             {
                 return new LocalizedString(name, value);
@@ -121,19 +121,19 @@ public class RemoteLocalizationContributor : ILocalizationResourceContributor
         return Task.FromResult((IEnumerable<string>)Array.Empty<string>());
     }
 
-    protected virtual ApplicationLocalizationResourceDto GetResourceOrNull(string resourceName)
+    protected virtual ApplicationLocalizationResourceDto? GetResourceOrNull(string resourceName)
     {
         var applicationConfigurationDto = _applicationConfigurationClient.Get();
         return GetResourceOrNull(applicationConfigurationDto, resourceName);
     }
     
-    protected virtual async Task<ApplicationLocalizationResourceDto> GetResourceOrNullAsync(string resourceName)
+    protected virtual async Task<ApplicationLocalizationResourceDto?> GetResourceOrNullAsync(string resourceName)
     {
         var applicationConfigurationDto = await _applicationConfigurationClient.GetAsync();
         return GetResourceOrNull(applicationConfigurationDto, resourceName);
     }
 
-    protected virtual ApplicationLocalizationResourceDto GetResourceOrNull(
+    protected virtual ApplicationLocalizationResourceDto? GetResourceOrNull(
         ApplicationConfigurationDto applicationConfigurationDto,
         string resourceName)
     {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteSettingProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteSettingProvider.cs
index 2599df1ef6..6553ee9881 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteSettingProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Client.Common/Volo/Abp/AspNetCore/Mvc/Client/RemoteSettingProvider.cs
@@ -15,7 +15,7 @@ public class RemoteSettingProvider : ISettingProvider, ITransientDependency
         ConfigurationClient = configurationClient;
     }
 
-    public async Task<string> GetOrNullAsync(string name)
+    public async Task<string?> GetOrNullAsync(string name)
     {
         var configuration = await ConfigurationClient.GetAsync();
         return configuration.Setting.Values.GetOrDefault(name);
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo.Abp.AspNetCore.Mvc.Client.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo.Abp.AspNetCore.Mvc.Client.csproj
index 2e5a66d740..39f753a6c0 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo.Abp.AspNetCore.Mvc.Client.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo.Abp.AspNetCore.Mvc.Client.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.AspNetCore.Mvc.Client</AssemblyName>
     <PackageId>Volo.Abp.AspNetCore.Mvc.Client</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo/Abp/AspNetCore/Mvc/Client/MvcCachedApplicationConfigurationClient.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo/Abp/AspNetCore/Mvc/Client/MvcCachedApplicationConfigurationClient.cs
index 6f2cc1a05f..b7d8a0df40 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo/Abp/AspNetCore/Mvc/Client/MvcCachedApplicationConfigurationClient.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo/Abp/AspNetCore/Mvc/Client/MvcCachedApplicationConfigurationClient.cs
@@ -47,14 +47,14 @@ public class MvcCachedApplicationConfigurationClient : ICachedApplicationConfigu
             return configuration;
         }
 
-        configuration = await Cache.GetOrAddAsync(
+        configuration = (await Cache.GetOrAddAsync(
             cacheKey,
             async () => await GetRemoteConfigurationAsync(),
             () => new DistributedCacheEntryOptions
             {
                 AbsoluteExpirationRelativeToNow = Options.ApplicationConfigurationDtoCacheAbsoluteExpiration
             }
-        );
+        ))!;
 
         if (httpContext != null)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo/Abp/AspNetCore/Mvc/Client/MvcRemoteTenantStore.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo/Abp/AspNetCore/Mvc/Client/MvcRemoteTenantStore.cs
index 3f091f8db8..aa9fc4beb8 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo/Abp/AspNetCore/Mvc/Client/MvcRemoteTenantStore.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Client/Volo/Abp/AspNetCore/Mvc/Client/MvcRemoteTenantStore.cs
@@ -31,7 +31,7 @@ public class MvcRemoteTenantStore : ITenantStore, ITransientDependency
         Options = options.Value;
     }
 
-    public async Task<TenantConfiguration> FindAsync(string name)
+    public async Task<TenantConfiguration?> FindAsync(string name)
     {
         var cacheKey = CreateCacheKey(name);
         var httpContext = HttpContextAccessor?.HttpContext;
@@ -41,14 +41,14 @@ public class MvcRemoteTenantStore : ITenantStore, ITransientDependency
             return tenantConfiguration;
         }
 
-        tenantConfiguration = await Cache.GetOrAddAsync(
+        tenantConfiguration = (await Cache.GetOrAddAsync(
             cacheKey,
-            async () => CreateTenantConfiguration(await TenantAppService.FindTenantByNameAsync(name)),
+            async () => CreateTenantConfiguration(await TenantAppService.FindTenantByNameAsync(name))!,
             () => new DistributedCacheEntryOptions
             {
                 AbsoluteExpirationRelativeToNow = Options.TenantConfigurationCacheAbsoluteExpiration
             }
-        );
+        ))!;
 
         if (httpContext != null)
         {
@@ -58,7 +58,7 @@ public class MvcRemoteTenantStore : ITenantStore, ITransientDependency
         return tenantConfiguration;
     }
 
-    public async Task<TenantConfiguration> FindAsync(Guid id)
+    public async Task<TenantConfiguration?> FindAsync(Guid id)
     {
         var cacheKey = CreateCacheKey(id);
         var httpContext = HttpContextAccessor?.HttpContext;
@@ -68,14 +68,14 @@ public class MvcRemoteTenantStore : ITenantStore, ITransientDependency
             return tenantConfiguration;
         }
 
-        tenantConfiguration = await Cache.GetOrAddAsync(
+        tenantConfiguration = (await Cache.GetOrAddAsync(
             cacheKey,
-            async () => CreateTenantConfiguration(await TenantAppService.FindTenantByIdAsync(id)),
+            async () => CreateTenantConfiguration(await TenantAppService.FindTenantByIdAsync(id))!,
             () => new DistributedCacheEntryOptions
             {
                 AbsoluteExpirationRelativeToNow = Options.TenantConfigurationCacheAbsoluteExpiration
             }
-        );
+        ))!;
 
         if (httpContext != null)
         {
@@ -97,12 +97,12 @@ public class MvcRemoteTenantStore : ITenantStore, ITransientDependency
 
         tenantConfiguration = Cache.GetOrAdd(
             cacheKey,
-            () => AsyncHelper.RunSync(async () => CreateTenantConfiguration(await TenantAppService.FindTenantByNameAsync(name))),
+            () => AsyncHelper.RunSync(async () => CreateTenantConfiguration(await TenantAppService.FindTenantByNameAsync(name))!),
             () => new DistributedCacheEntryOptions
             {
                 AbsoluteExpirationRelativeToNow = Options.TenantConfigurationCacheAbsoluteExpiration
             }
-        );
+        )!;
 
         if (httpContext != null)
         {
@@ -124,12 +124,12 @@ public class MvcRemoteTenantStore : ITenantStore, ITransientDependency
 
         tenantConfiguration = Cache.GetOrAdd(
             cacheKey,
-            () => AsyncHelper.RunSync(async () => CreateTenantConfiguration(await TenantAppService.FindTenantByIdAsync(id))),
+            () => AsyncHelper.RunSync(async () => CreateTenantConfiguration(await TenantAppService.FindTenantByIdAsync(id))!),
             () => new DistributedCacheEntryOptions
             {
                 AbsoluteExpirationRelativeToNow = Options.TenantConfigurationCacheAbsoluteExpiration
             }
-        );
+        )!;
 
         if (httpContext != null)
         {
@@ -139,14 +139,14 @@ public class MvcRemoteTenantStore : ITenantStore, ITransientDependency
         return tenantConfiguration;
     }
 
-    protected virtual TenantConfiguration CreateTenantConfiguration(FindTenantResultDto tenantResultDto)
+    protected virtual TenantConfiguration? CreateTenantConfiguration(FindTenantResultDto tenantResultDto)
     {
         if (!tenantResultDto.Success || tenantResultDto.TenantId == null)
         {
             return null;
         }
 
-        return new TenantConfiguration(tenantResultDto.TenantId.Value, tenantResultDto.Name);
+        return new TenantConfiguration(tenantResultDto.TenantId.Value, tenantResultDto.Name!);
     }
 
     protected virtual string CreateCacheKey(string tenantName)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo.Abp.AspNetCore.Mvc.Contracts.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo.Abp.AspNetCore.Mvc.Contracts.csproj
index a89f7c60a7..e0ddc7cdbe 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo.Abp.AspNetCore.Mvc.Contracts.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo.Abp.AspNetCore.Mvc.Contracts.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.AspNetCore.Mvc.Contracts</AssemblyName>
     <PackageId>Volo.Abp.AspNetCore.Mvc.Contracts</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationConfigurationDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationConfigurationDto.cs
index 61b5ec18db..e9c079cc84 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationConfigurationDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationConfigurationDto.cs
@@ -31,4 +31,20 @@ public class ApplicationConfigurationDto : IHasExtraProperties
     public ObjectExtensionsDto ObjectExtensions { get; set; }
 
     public ExtraPropertyDictionary ExtraProperties { get; set; }
+
+    public ApplicationConfigurationDto()
+    {
+        Localization = new ApplicationLocalizationConfigurationDto();
+        Auth = new ApplicationAuthConfigurationDto();
+        Setting = new ApplicationSettingConfigurationDto();
+        CurrentUser = new CurrentUserDto();
+        Features = new ApplicationFeatureConfigurationDto();
+        GlobalFeatures = new ApplicationGlobalFeatureConfigurationDto();
+        MultiTenancy = new MultiTenancyInfoDto();
+        CurrentTenant = new CurrentTenantDto();
+        Timing = new TimingDto();
+        Clock = new ClockDto();
+        ObjectExtensions = new ObjectExtensionsDto();
+        ExtraProperties = new ExtraPropertyDictionary();
+    }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationConfigurationDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationConfigurationDto.cs
index b1c0c16e76..5ae2a8ed2d 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationConfigurationDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationConfigurationDto.cs
@@ -28,7 +28,7 @@ public class ApplicationLocalizationConfigurationDto
 
     public CurrentCultureDto CurrentCulture { get; set; }
 
-    public string DefaultResourceName { get; set; }
+    public string? DefaultResourceName { get; set; }
 
     public Dictionary<string, List<NameValue>> LanguagesMap { get; set; }
 
@@ -38,5 +38,8 @@ public class ApplicationLocalizationConfigurationDto
     {
         Values = new Dictionary<string, Dictionary<string, string>>();
         Languages = new List<LanguageInfo>();
+        CurrentCulture = new CurrentCultureDto();
+        LanguagesMap = new Dictionary<string, List<NameValue>>();
+        LanguageFilesMap = new Dictionary<string, List<NameValue>>();
     }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationDto.cs
index d301490bed..2bbc604c95 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationDto.cs
@@ -7,4 +7,9 @@ namespace Volo.Abp.AspNetCore.Mvc.ApplicationConfigurations;
 public class ApplicationLocalizationDto
 {
     public Dictionary<string, ApplicationLocalizationResourceDto> Resources { get; set; }
+
+    public ApplicationLocalizationDto()
+    {
+        Resources = new Dictionary<string, ApplicationLocalizationResourceDto>();
+    }
 }
\ No newline at end of file
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationRequestDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationRequestDto.cs
index 535d572b3f..3b6debe695 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationRequestDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationRequestDto.cs
@@ -5,7 +5,7 @@ namespace Volo.Abp.AspNetCore.Mvc.ApplicationConfigurations;
 public class ApplicationLocalizationRequestDto
 {
     [Required]
-    public string CultureName { get; set; }
+    public string CultureName { get; set; } = default!;
     
     public bool OnlyDynamics { get; set; }
 }
\ No newline at end of file
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationResourceDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationResourceDto.cs
index a7200423d2..bca4ccd8ee 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationResourceDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationLocalizationResourceDto.cs
@@ -7,6 +7,11 @@ namespace Volo.Abp.AspNetCore.Mvc.ApplicationConfigurations;
 public class ApplicationLocalizationResourceDto
 {
     public Dictionary<string, string> Texts { get; set; }
-    
-    public string[] BaseResources { get; set; }
+
+    public string[] BaseResources { get; set; } = default!;
+
+    public ApplicationLocalizationResourceDto()
+    {
+        Texts = new Dictionary<string, string>();
+    }
 }
\ No newline at end of file
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationSettingConfigurationDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationSettingConfigurationDto.cs
index a1fbba2bbf..1ae30828cf 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationSettingConfigurationDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ApplicationSettingConfigurationDto.cs
@@ -6,5 +6,10 @@ namespace Volo.Abp.AspNetCore.Mvc.ApplicationConfigurations;
 [Serializable]
 public class ApplicationSettingConfigurationDto
 {
-    public Dictionary<string, string> Values { get; set; }
+    public Dictionary<string, string?> Values { get; set; }
+
+    public ApplicationSettingConfigurationDto()
+    {
+        Values = new Dictionary<string, string?>();
+    }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ClockDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ClockDto.cs
index 5112ac80ed..96cd5bd38b 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ClockDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ClockDto.cs
@@ -2,5 +2,5 @@
 
 public class ClockDto
 {
-    public string Kind { get; set; }
+    public string Kind { get; set; } = default!;
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/CurrentCultureDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/CurrentCultureDto.cs
index 83f1e0c803..054e626844 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/CurrentCultureDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/CurrentCultureDto.cs
@@ -5,21 +5,21 @@ namespace Volo.Abp.AspNetCore.Mvc.ApplicationConfigurations;
 [Serializable]
 public class CurrentCultureDto
 {
-    public string DisplayName { get; set; }
+    public string DisplayName { get; set; } = default!;
 
-    public string EnglishName { get; set; }
+    public string EnglishName { get; set; } = default!;
 
-    public string ThreeLetterIsoLanguageName { get; set; }
+    public string ThreeLetterIsoLanguageName { get; set; } = default!;
 
-    public string TwoLetterIsoLanguageName { get; set; }
+    public string TwoLetterIsoLanguageName { get; set; } = default!;
 
     public bool IsRightToLeft { get; set; }
 
-    public string CultureName { get; set; }
+    public string CultureName { get; set; } = default!;
 
-    public string Name { get; set; }
+    public string Name { get; set; } = default!;
 
-    public string NativeName { get; set; }
+    public string NativeName { get; set; } = default!;
 
-    public DateTimeFormatDto DateTimeFormat { get; set; }
+    public DateTimeFormatDto DateTimeFormat { get; set; } = default!;
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/CurrentUserDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/CurrentUserDto.cs
index 08a8c4c873..63a4b7a0e9 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/CurrentUserDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/CurrentUserDto.cs
@@ -15,23 +15,23 @@ public class CurrentUserDto
 
     public Guid? ImpersonatorTenantId { get; set; }
 
-    public string ImpersonatorUserName { get; set; }
+    public string? ImpersonatorUserName { get; set; }
 
-    public string ImpersonatorTenantName { get; set; }
+    public string? ImpersonatorTenantName { get; set; }
 
-    public string UserName { get; set; }
+    public string? UserName { get; set; }
 
-    public string Name { get; set; }
+    public string? Name { get; set; }
 
-    public string SurName { get; set; }
+    public string? SurName { get; set; }
 
-    public string Email { get; set; }
+    public string? Email { get; set; }
 
     public bool EmailVerified { get; set; }
 
-    public string PhoneNumber { get; set; }
+    public string? PhoneNumber { get; set; }
 
     public bool PhoneNumberVerified { get; set; }
 
-    public string[] Roles { get; set; }
+    public string[] Roles { get; set; } = default!;
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/DateTimeFormatDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/DateTimeFormatDto.cs
index 5f5ad14a5a..a16282efdd 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/DateTimeFormatDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/DateTimeFormatDto.cs
@@ -2,17 +2,17 @@
 
 public class DateTimeFormatDto
 {
-    public string CalendarAlgorithmType { get; set; }
+    public string CalendarAlgorithmType { get; set; } = default!;
 
-    public string DateTimeFormatLong { get; set; }
+    public string DateTimeFormatLong { get; set; } = default!;
 
-    public string ShortDatePattern { get; set; }
+    public string ShortDatePattern { get; set; } = default!;
 
-    public string FullDateTimePattern { get; set; }
+    public string FullDateTimePattern { get; set; } = default!;
 
-    public string DateSeparator { get; set; }
+    public string DateSeparator { get; set; } = default!;
 
-    public string ShortTimePattern { get; set; }
+    public string ShortTimePattern { get; set; } = default!;
 
-    public string LongTimePattern { get; set; }
+    public string LongTimePattern { get; set; } = default!;
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/EntityExtensionDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/EntityExtensionDto.cs
index 742da779f6..533349527c 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/EntityExtensionDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/EntityExtensionDto.cs
@@ -9,4 +9,10 @@ public class EntityExtensionDto
     public Dictionary<string, ExtensionPropertyDto> Properties { get; set; }
 
     public Dictionary<string, object> Configuration { get; set; }
+
+    public EntityExtensionDto()
+    {
+        Properties = new Dictionary<string, ExtensionPropertyDto>();
+        Configuration = new Dictionary<string, object>();
+    }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionEnumDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionEnumDto.cs
index 24e9ec9a2f..cd1d210005 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionEnumDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionEnumDto.cs
@@ -8,5 +8,10 @@ public class ExtensionEnumDto
 {
     public List<ExtensionEnumFieldDto> Fields { get; set; }
 
-    public string LocalizationResource { get; set; }
+    public string? LocalizationResource { get; set; }
+
+    public ExtensionEnumDto()
+    {
+        Fields = new List<ExtensionEnumFieldDto>();
+    }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionEnumFieldDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionEnumFieldDto.cs
index 13728d8409..03c0213015 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionEnumFieldDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionEnumFieldDto.cs
@@ -5,7 +5,7 @@ namespace Volo.Abp.AspNetCore.Mvc.ApplicationConfigurations.ObjectExtending;
 [Serializable]
 public class ExtensionEnumFieldDto
 {
-    public string Name { get; set; }
+    public string? Name { get; set; }
 
-    public object Value { get; set; }
+    public object? Value { get; set; }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyAttributeDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyAttributeDto.cs
index 492756168d..ea28fb3cb9 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyAttributeDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyAttributeDto.cs
@@ -6,7 +6,12 @@ namespace Volo.Abp.AspNetCore.Mvc.ApplicationConfigurations.ObjectExtending;
 [Serializable]
 public class ExtensionPropertyAttributeDto
 {
-    public string TypeSimple { get; set; }
+    public string TypeSimple { get; set; } = default!;
 
     public Dictionary<string, object> Config { get; set; }
+
+    public ExtensionPropertyAttributeDto()
+    {
+        Config = new Dictionary<string, object>();
+    }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyDto.cs
index a1fb628e1a..68a915309d 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyDto.cs
@@ -7,12 +7,11 @@ namespace Volo.Abp.AspNetCore.Mvc.ApplicationConfigurations.ObjectExtending;
 [Serializable]
 public class ExtensionPropertyDto
 {
-    public string Type { get; set; }
+    public string Type { get; set; } = default!;
 
-    public string TypeSimple { get; set; }
+    public string TypeSimple { get; set; } = default!;
 
-    [CanBeNull]
-    public LocalizableStringDto DisplayName { get; set; }
+    public LocalizableStringDto? DisplayName { get; set; }
 
     public ExtensionPropertyApiDto Api { get; set; }
 
@@ -22,5 +21,13 @@ public class ExtensionPropertyDto
 
     public Dictionary<string, object> Configuration { get; set; }
 
-    public object DefaultValue { get; set; }
+    public object? DefaultValue { get; set; }
+
+    public ExtensionPropertyDto()
+    {
+        Api = new ExtensionPropertyApiDto();
+        Ui = new ExtensionPropertyUiDto();
+        Attributes = new List<ExtensionPropertyAttributeDto>();
+        Configuration = new Dictionary<string, object>();
+    }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyUiDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyUiDto.cs
index cd43df5446..2c90299b15 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyUiDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyUiDto.cs
@@ -9,4 +9,12 @@ public class ExtensionPropertyUiDto
     public ExtensionPropertyUiFormDto OnCreateForm { get; set; }
     public ExtensionPropertyUiFormDto OnEditForm { get; set; }
     public ExtensionPropertyUiLookupDto Lookup { get; set; }
+    
+    public ExtensionPropertyUiDto()
+    {
+        OnTable = new ExtensionPropertyUiTableDto();
+        OnCreateForm = new ExtensionPropertyUiFormDto();
+        OnEditForm = new ExtensionPropertyUiFormDto();
+        Lookup = new ExtensionPropertyUiLookupDto();
+    }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyUiLookupDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyUiLookupDto.cs
index b9bc94399c..ae5fd451de 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyUiLookupDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyUiLookupDto.cs
@@ -5,9 +5,9 @@ namespace Volo.Abp.AspNetCore.Mvc.ApplicationConfigurations.ObjectExtending;
 [Serializable]
 public class ExtensionPropertyUiLookupDto
 {
-    public string Url { get; set; }
-    public string ResultListPropertyName { get; set; }
-    public string DisplayPropertyName { get; set; }
-    public string ValuePropertyName { get; set; }
-    public string FilterParamName { get; set; }
+    public string Url { get; set; } = default!;
+    public string ResultListPropertyName { get; set; } = default!;
+    public string DisplayPropertyName { get; set; } = default!;
+    public string ValuePropertyName { get; set; } = default!;
+    public string FilterParamName { get; set; } = default!;
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/LocalizableStringDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/LocalizableStringDto.cs
index 8127a90bd7..2fc1989ad5 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/LocalizableStringDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/LocalizableStringDto.cs
@@ -9,10 +9,9 @@ public class LocalizableStringDto
     [NotNull]
     public string Name { get; private set; }
 
-    [CanBeNull]
-    public string Resource { get; set; }
+    public string? Resource { get; set; }
 
-    public LocalizableStringDto([NotNull] string name, string resource = null)
+    public LocalizableStringDto([NotNull] string name, string? resource = null)
     {
         Name = Check.NotNullOrEmpty(name, nameof(name));
         Resource = resource;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ModuleExtensionDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ModuleExtensionDto.cs
index aadd08cd28..50c944f6ec 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ModuleExtensionDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ModuleExtensionDto.cs
@@ -9,4 +9,10 @@ public class ModuleExtensionDto
     public Dictionary<string, EntityExtensionDto> Entities { get; set; }
 
     public Dictionary<string, object> Configuration { get; set; }
+
+    public ModuleExtensionDto()
+    {
+        Entities = new Dictionary<string, EntityExtensionDto>();
+        Configuration = new Dictionary<string, object>();
+    }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ObjectExtensionsDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ObjectExtensionsDto.cs
index f63935847b..b07855057b 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ObjectExtensionsDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ObjectExtensionsDto.cs
@@ -9,4 +9,10 @@ public class ObjectExtensionsDto
     public Dictionary<string, ModuleExtensionDto> Modules { get; set; }
 
     public Dictionary<string, ExtensionEnumDto> Enums { get; set; }
+
+    public ObjectExtensionsDto()
+    {
+        Modules = new Dictionary<string, ModuleExtensionDto>();
+        Enums = new Dictionary<string, ExtensionEnumDto>();
+    }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/TimingDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/TimingDto.cs
index ca03407ee5..7aa38ede79 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/TimingDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/TimingDto.cs
@@ -3,6 +3,11 @@
 public class TimingDto
 {
     public TimeZone TimeZone { get; set; }
+
+    public TimingDto()
+    {
+        TimeZone = new TimeZone();
+    }
 }
 
 public class TimeZone
@@ -10,14 +15,20 @@ public class TimeZone
     public IanaTimeZone Iana { get; set; }
 
     public WindowsTimeZone Windows { get; set; }
+
+    public TimeZone()
+    {
+        Iana = new IanaTimeZone();
+        Windows = new WindowsTimeZone();
+    }
 }
 
 public class WindowsTimeZone
 {
-    public string TimeZoneId { get; set; }
+    public string? TimeZoneId { get; set; }
 }
 
 public class IanaTimeZone
 {
-    public string TimeZoneName { get; set; }
+    public string? TimeZoneName { get; set; }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/MultiTenancy/CurrentTenantDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/MultiTenancy/CurrentTenantDto.cs
index b8b361e7c8..d8c1351b3e 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/MultiTenancy/CurrentTenantDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/MultiTenancy/CurrentTenantDto.cs
@@ -8,7 +8,7 @@ public class CurrentTenantDto
 {
     public Guid? Id { get; set; }
 
-    public string Name { get; set; }
+    public string? Name { get; set; }
 
     public bool IsAvailable { get; set; }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/MultiTenancy/FindTenantResultDto.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/MultiTenancy/FindTenantResultDto.cs
index 64bcc77554..599b0b8a67 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/MultiTenancy/FindTenantResultDto.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.Contracts/Volo/Abp/AspNetCore/Mvc/MultiTenancy/FindTenantResultDto.cs
@@ -9,7 +9,7 @@ public class FindTenantResultDto
 
     public Guid? TenantId { get; set; }
 
-    public string Name { get; set; }
+    public string? Name { get; set; }
 
     public bool IsActive { get; set; }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.NewtonsoftJson/Volo.Abp.AspNetCore.Mvc.NewtonsoftJson.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.NewtonsoftJson/Volo.Abp.AspNetCore.Mvc.NewtonsoftJson.csproj
index 026fb2f4d4..bd0d7c063f 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.NewtonsoftJson/Volo.Abp.AspNetCore.Mvc.NewtonsoftJson.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.NewtonsoftJson/Volo.Abp.AspNetCore.Mvc.NewtonsoftJson.csproj
@@ -5,6 +5,8 @@
 
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <WarningsAsErrors>Nullable</WarningsAsErrors>
         <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
         <AssemblyName>Volo.Abp.AspNetCore.Mvc.NewtonsoftJson</AssemblyName>
         <PackageId>Volo.Abp.AspNetCore.Mvc.NewtonsoftJson</PackageId>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/Microsoft/AspNetCore/Razor/TagHelpers/AbpTagHelperAttributeListExtensions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/Microsoft/AspNetCore/Razor/TagHelpers/AbpTagHelperAttributeListExtensions.cs
index 81aefb7382..def91ef68b 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/Microsoft/AspNetCore/Razor/TagHelpers/AbpTagHelperAttributeListExtensions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/Microsoft/AspNetCore/Razor/TagHelpers/AbpTagHelperAttributeListExtensions.cs
@@ -22,7 +22,7 @@ public static class AbpTagHelperAttributeListExtensions
         }
         else
         {
-            var existingClasses = classAttribute.Value.ToString().Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).ToList();
+            var existingClasses = classAttribute.Value.ToString()!.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).ToList();
             existingClasses.AddIfNotContains(className);
             attributes.SetAttribute("class", string.Join(" ", existingClasses));
         }
@@ -41,7 +41,7 @@ public static class AbpTagHelperAttributeListExtensions
             return;
         }
 
-        var classList = classAttribute.Value.ToString().Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).ToList();
+        var classList = classAttribute.Value.ToString()!.Split(new[] { ' ' }, StringSplitOptions.RemoveEmptyEntries).ToList();
         classList.RemoveAll(c => c == className);
 
         attributes.SetAttribute("class", classList.JoinAsString(" "));
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelper.cs
index 5b9c1430f2..8d0227fd11 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelper.cs
@@ -23,7 +23,7 @@ public abstract class AbpTagHelper<TTagHelper, TService> : AbpTagHelper
 
     [HtmlAttributeNotBound]
     [ViewContext]
-    public ViewContext ViewContext { get; set; }
+    public ViewContext ViewContext { get; set; } = default!;
 
     protected AbpTagHelper(TService service)
     {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelperLocalizer.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelperLocalizer.cs
index c4314134be..5b6db4ff17 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelperLocalizer.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelperLocalizer.cs
@@ -27,12 +27,12 @@ public class AbpTagHelperLocalizer : IAbpTagHelperLocalizer
             : localizer[text].Value;
     }
 
-    public IStringLocalizer GetLocalizerOrNull(ModelExplorer explorer)
+    public IStringLocalizer? GetLocalizerOrNull(ModelExplorer explorer)
     {
         return GetLocalizerOrNull(explorer.Container.ModelType.Assembly);
     }
 
-    public IStringLocalizer GetLocalizerOrNull(Assembly assembly)
+    public IStringLocalizer? GetLocalizerOrNull(Assembly assembly)
     {
         var resourceType = GetResourceType(assembly);
         return resourceType == null
@@ -40,7 +40,7 @@ public class AbpTagHelperLocalizer : IAbpTagHelperLocalizer
             : _stringLocalizerFactory.Create(resourceType);
     }
 
-    private Type GetResourceType(Assembly assembly)
+    private Type? GetResourceType(Assembly assembly)
     {
         return _options
             .AssemblyResources
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelperService.cs
index b9c3aa92e6..95de4f7f51 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/AbpTagHelperService.cs
@@ -23,7 +23,7 @@ public abstract class AbpTagHelperService<TTagHelper> : IAbpTagHelperService<TTa
     protected const string AbpTabItemSelectedPlaceholder = "{_Tab_Selected_Placeholder_}";
     protected const string AbpAccordionParentIdPlaceholder = "{_Parent_Accordion_Id_}";
 
-    public TTagHelper TagHelper { get; internal set; }
+    public TTagHelper TagHelper { get; internal set; } = default!;
 
     public virtual int Order { get; }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Breadcrumb/AbpBreadcrumbItemTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Breadcrumb/AbpBreadcrumbItemTagHelper.cs
index 71ce3406fa..650b1efb0a 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Breadcrumb/AbpBreadcrumbItemTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Breadcrumb/AbpBreadcrumbItemTagHelper.cs
@@ -2,9 +2,9 @@
 
 public class AbpBreadcrumbItemTagHelper : AbpTagHelper<AbpBreadcrumbItemTagHelper, AbpBreadcrumbItemTagHelperService>
 {
-    public string Href { get; set; }
+    public string? Href { get; set; }
 
-    public string Title { get; set; }
+    public string Title { get; set; } = default!;
 
     public bool Active { get; set; }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Breadcrumb/BreadcrumbItem.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Breadcrumb/BreadcrumbItem.cs
index 37a194b906..de9f59ca01 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Breadcrumb/BreadcrumbItem.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Breadcrumb/BreadcrumbItem.cs
@@ -2,7 +2,7 @@
 
 public class BreadcrumbItem
 {
-    public string Html { get; set; }
+    public string Html { get; set; } = default!;
 
     public bool Active { get; set; }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpButtonTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpButtonTagHelper.cs
index 624d750274..60c986f34b 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpButtonTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpButtonTagHelper.cs
@@ -9,11 +9,11 @@ public class AbpButtonTagHelper : AbpTagHelper<AbpButtonTagHelper, AbpButtonTagH
 
     public AbpButtonSize Size { get; set; } = AbpButtonSize.Default;
 
-    public string BusyText { get; set; }
+    public string? BusyText { get; set; }
 
-    public string Text { get; set; }
+    public string? Text { get; set; }
 
-    public string Icon { get; set; }
+    public string? Icon { get; set; }
 
     public bool? Disabled { get; set; }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpButtonTagHelperServiceBase.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpButtonTagHelperServiceBase.cs
index 17422327c8..a69d09eed4 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpButtonTagHelperServiceBase.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpButtonTagHelperServiceBase.cs
@@ -57,7 +57,7 @@ public abstract class AbpButtonTagHelperServiceBase<TTagHelper> : AbpTagHelperSe
             case FontIconType.FontAwesome:
                 return "fa fa-" + TagHelper.Icon;
             default:
-                return TagHelper.Icon;
+                return TagHelper.Icon!;
         }
     }
 
@@ -69,7 +69,7 @@ public abstract class AbpButtonTagHelperServiceBase<TTagHelper> : AbpTagHelperSe
         }
 
         var span = new TagBuilder("span");
-        span.InnerHtml.AppendHtml(TagHelper.Text);
+        span.InnerHtml.AppendHtml(TagHelper.Text!);
         output.Content.AppendHtml(span);
     }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpLinkButtonTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpLinkButtonTagHelper.cs
index bf3b4d8bac..53508864cd 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpLinkButtonTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/AbpLinkButtonTagHelper.cs
@@ -11,9 +11,9 @@ public class AbpLinkButtonTagHelper : AbpTagHelper<AbpLinkButtonTagHelper, AbpLi
 
     public AbpButtonSize Size { get; set; } = AbpButtonSize.Default;
 
-    public string Text { get; set; }
+    public string? Text { get; set; }
 
-    public string Icon { get; set; }
+    public string? Icon { get; set; }
 
     public bool? Disabled { get; set; }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/IButtonTagHelperBase.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/IButtonTagHelperBase.cs
index 8ba73b2ab9..56e48c83de 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/IButtonTagHelperBase.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Button/IButtonTagHelperBase.cs
@@ -6,9 +6,9 @@ public interface IButtonTagHelperBase
 
     AbpButtonSize Size { get; }
 
-    string Text { get; }
+    string? Text { get; }
 
-    string Icon { get; }
+    string? Icon { get; }
 
     bool? Disabled { get; }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Card/AbpCardBodyTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Card/AbpCardBodyTagHelper.cs
index 34a14e6f33..c33293e13f 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Card/AbpCardBodyTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Card/AbpCardBodyTagHelper.cs
@@ -2,9 +2,9 @@
 
 public class AbpCardBodyTagHelper : AbpTagHelper<AbpCardBodyTagHelper, AbpCardBodyTagHelperService>
 {
-    public string Title { get; set; }
+    public string? Title { get; set; }
 
-    public string Subtitle { get; set; }
+    public string? Subtitle { get; set; }
 
     public AbpCardBodyTagHelper(AbpCardBodyTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Card/AbpCardBodyTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Card/AbpCardBodyTagHelperService.cs
index 172fa778b6..e50d0a791a 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Card/AbpCardBodyTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Card/AbpCardBodyTagHelperService.cs
@@ -22,7 +22,7 @@ public class AbpCardBodyTagHelperService : AbpTagHelperService<AbpCardBodyTagHel
         {
             var cardTitle = new TagBuilder(AbpCardTitleTagHelper.DefaultHeading.ToHtmlTag());
             cardTitle.AddCssClass("card-title");
-            cardTitle.InnerHtml.AppendHtml(TagHelper.Title);
+            cardTitle.InnerHtml.AppendHtml(TagHelper.Title!);
             output.PreContent.AppendHtml(cardTitle);
         }
     }
@@ -33,7 +33,7 @@ public class AbpCardBodyTagHelperService : AbpTagHelperService<AbpCardBodyTagHel
         {
             var cardSubtitle = new TagBuilder(AbpCardSubtitleTagHelper.DefaultHeading.ToHtmlTag());
             cardSubtitle.AddCssClass("card-subtitle text-muted mb-2");
-            cardSubtitle.InnerHtml.AppendHtml(TagHelper.Subtitle);
+            cardSubtitle.InnerHtml.AppendHtml(TagHelper.Subtitle!);
             output.PreContent.AppendHtml(cardSubtitle);
         }
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselItemTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselItemTagHelper.cs
index 65a47b73c4..3a1f82fb51 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselItemTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselItemTagHelper.cs
@@ -4,13 +4,13 @@ public class AbpCarouselItemTagHelper : AbpTagHelper<AbpCarouselItemTagHelper, A
 {
     public bool? Active { get; set; }
 
-    public string Src { get; set; }
+    public string Src { get; set; } = default!;
 
-    public string Alt { get; set; }
+    public string Alt { get; set; } = default!;
 
-    public string CaptionTitle { get; set; }
+    public string? CaptionTitle { get; set; }
 
-    public string Caption { get; set; }
+    public string? Caption { get; set; }
 
     public AbpCarouselItemTagHelper(AbpCarouselItemTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselItemTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselItemTagHelperService.cs
index a8a3030e95..370d781f04 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselItemTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselItemTagHelperService.cs
@@ -66,10 +66,10 @@ public class AbpCarouselItemTagHelperService : AbpTagHelperService<AbpCarouselIt
         }
 
         var title = new TagBuilder("h5");
-        title.InnerHtml.AppendHtml(TagHelper.CaptionTitle);
+        title.InnerHtml.AppendHtml(TagHelper.CaptionTitle!);
 
         var caption = new TagBuilder("p");
-        caption.InnerHtml.AppendHtml(TagHelper.Caption);
+        caption.InnerHtml.AppendHtml(TagHelper.Caption!);
 
         var wrapper = new TagBuilder("div");
         wrapper.AddCssClass("carousel-caption d-none d-md-block");
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselTagHelper.cs
index e9931241c2..eb9cac08f1 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselTagHelper.cs
@@ -2,7 +2,7 @@
 
 public class AbpCarouselTagHelper : AbpTagHelper<AbpCarouselTagHelper, AbpCarouselTagHelperService>
 {
-    public string Id { get; set; }
+    public string? Id { get; set; }
 
     public bool? Crossfade { get; set; }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselTagHelperService.cs
index 9264737b7b..af81b045f5 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Carousel/AbpCarouselTagHelperService.cs
@@ -138,7 +138,7 @@ public class AbpCarouselTagHelperService : AbpTagHelperService<AbpCarouselTagHel
     {
         if (!itemList.Any(it => it.Active) && itemList.Count > 0)
         {
-            itemList.FirstOrDefault().Active = true;
+            itemList.FirstOrDefault()!.Active = true;
         }
     }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpAccordionItemTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpAccordionItemTagHelper.cs
index 8742631e9a..99dd4ff3a1 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpAccordionItemTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpAccordionItemTagHelper.cs
@@ -2,9 +2,9 @@
 
 public class AbpAccordionItemTagHelper : AbpTagHelper<AbpAccordionItemTagHelper, AbpAccordionItemTagHelperService>
 {
-    public string Id { get; set; }
+    public string? Id { get; set; }
 
-    public string Title { get; set; }
+    public string Title { get; set; } = default!;
 
     public bool? Active { get; set; }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpAccordionTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpAccordionTagHelper.cs
index 49cca3199f..a4a87ab32a 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpAccordionTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpAccordionTagHelper.cs
@@ -2,7 +2,7 @@
 
 public class AbpAccordionTagHelper : AbpTagHelper<AbpAccordionTagHelper, AbpAccordionTagHelperService>
 {
-    public string Id { get; set; }
+    public string? Id { get; set; }
 
     public AbpAccordionTagHelper(AbpAccordionTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpCollapseBodyTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpCollapseBodyTagHelper.cs
index cd6d5d43ed..477c8ed1d8 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpCollapseBodyTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpCollapseBodyTagHelper.cs
@@ -2,7 +2,7 @@
 
 public class AbpCollapseBodyTagHelper : AbpTagHelper<AbpCollapseBodyTagHelper, AbpCollapseBodyTagHelperService>
 {
-    public string Id { get; set; }
+    public string? Id { get; set; }
 
     public bool? Multi { get; set; }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpCollapseButtonTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpCollapseButtonTagHelper.cs
index c1219b3bbb..64d90496c3 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpCollapseButtonTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Collapse/AbpCollapseButtonTagHelper.cs
@@ -8,7 +8,7 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Collapse;
 public class AbpCollapseButtonTagHelper : AbpTagHelper<AbpCollapseButtonTagHelper, AbpCollapseButtonTagHelperService>
 {
     [HtmlAttributeName("abp-collapse-id")]
-    public string BodyId { get; set; }
+    public string BodyId { get; set; } = default!;
 
     public AbpCollapseButtonTagHelper(AbpCollapseButtonTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Dropdown/AbpDropdownButtonTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Dropdown/AbpDropdownButtonTagHelper.cs
index ac87900307..bc0778cb47 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Dropdown/AbpDropdownButtonTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Dropdown/AbpDropdownButtonTagHelper.cs
@@ -4,7 +4,7 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Dropdown;
 
 public class AbpDropdownButtonTagHelper : AbpTagHelper<AbpDropdownButtonTagHelper, AbpDropdownButtonTagHelperService>
 {
-    public string Text { get; set; }
+    public string? Text { get; set; }
 
     public AbpButtonSize Size { get; set; } = AbpButtonSize.Default;
 
@@ -12,7 +12,7 @@ public class AbpDropdownButtonTagHelper : AbpTagHelper<AbpDropdownButtonTagHelpe
 
     public AbpButtonType ButtonType { get; set; } = AbpButtonType.Default;
 
-    public string Icon { get; set; }
+    public string? Icon { get; set; }
 
     public FontIconType IconType { get; set; } = FontIconType.FontAwesome;
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Extensions/ModelExplorerExtensions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Extensions/ModelExplorerExtensions.cs
index eced70b75e..0e33d425e7 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Extensions/ModelExplorerExtensions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Extensions/ModelExplorerExtensions.cs
@@ -7,9 +7,9 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Extensions;
 
 public static class ModelExplorerExtensions
 {
-    public static T GetAttribute<T>(this ModelExplorer property) where T : Attribute
+    public static T? GetAttribute<T>(this ModelExplorer property) where T : Attribute
     {
-        return property?.Metadata?.ContainerType?.GetTypeInfo()?.GetProperty(property.Metadata.PropertyName)?.GetCustomAttribute<T>();
+        return property?.Metadata?.ContainerType?.GetTypeInfo()?.GetProperty(property.Metadata.PropertyName!)?.GetCustomAttribute<T>();
     }
 
     public static int GetDisplayOrder(this ModelExplorer explorer)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Extensions/TagHelperContextExtensions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Extensions/TagHelperContextExtensions.cs
index 47ab8827e7..bda437f8c5 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Extensions/TagHelperContextExtensions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Extensions/TagHelperContextExtensions.cs
@@ -11,7 +11,7 @@ public static class TagHelperContextExtensions
     {
         if (!context.Items.ContainsKey(key))
         {
-            return default(T);
+            return default(T)!;
         }
 
         return (T)context.Items[key];
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpDynamicformTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpDynamicformTagHelper.cs
index 6f2ed964cb..4e4b86a308 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpDynamicformTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpDynamicformTagHelper.cs
@@ -12,7 +12,7 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Form;
 public class AbpDynamicFormTagHelper : AbpTagHelper<AbpDynamicFormTagHelper, AbpDynamicFormTagHelperService>
 {
     [HtmlAttributeName("abp-model")]
-    public ModelExpression Model { get; set; }
+    public ModelExpression Model { get; set; } = default!;
 
     [HtmlAttributeName("column-size")]
     public ColumnSize ColumnSize { get; set; }
@@ -23,7 +23,7 @@ public class AbpDynamicFormTagHelper : AbpTagHelper<AbpDynamicFormTagHelper, Abp
 
     #region MvcFormTagHelperAttiributes
     
-    private IDictionary<string, string> _routeValues;
+    private IDictionary<string, string>? _routeValues;
 
     private const string ActionAttributeName = "asp-action";
     private const string AreaAttributeName = "asp-area";
@@ -36,28 +36,28 @@ public class AbpDynamicFormTagHelper : AbpTagHelper<AbpDynamicFormTagHelper, Abp
     private const string RouteValuesPrefix = "asp-route-";
 
     [HtmlAttributeName(ActionAttributeName)]
-    public string Action { get; set; }
+    public string Action { get; set; } = default!;
 
     [HtmlAttributeName(ControllerAttributeName)]
-    public string Controller { get; set; }
+    public string Controller { get; set; } = default!;
 
     [HtmlAttributeName(AreaAttributeName)]
-    public string Area { get; set; }
+    public string Area { get; set; } = default!;
 
     [HtmlAttributeName(PageAttributeName)]
-    public string Page { get; set; }
+    public string Page { get; set; } = default!;
 
     [HtmlAttributeName(PageHandlerAttributeName)]
-    public string PageHandler { get; set; }
+    public string PageHandler { get; set; } = default!;
 
     [HtmlAttributeName(FragmentAttributeName)]
-    public string Fragment { get; set; }
+    public string Fragment { get; set; } = default!;
 
     [HtmlAttributeName(RouteAttributeName)]
-    public string Route { get; set; }
+    public string Route { get; set; } = default!;
 
     [EditorBrowsable(EditorBrowsableState.Never)]
-    public string Method { get; set; }
+    public string Method { get; set; } = default!;
 
     [HtmlAttributeName(RouteValuesDictionaryName, DictionaryAttributePrefix = RouteValuesPrefix)]
     public IDictionary<string, string> RouteValues
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpDynamicformTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpDynamicformTagHelperService.cs
index 5938ad356d..57fa9fe0fb 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpDynamicformTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpDynamicformTagHelperService.cs
@@ -201,7 +201,7 @@ public class AbpDynamicFormTagHelperService : AbpTagHelperService<AbpDynamicForm
 
     private AbpTagHelper GetAbpDateRangeInputTagHelper(TagHelperContext context, TagHelperOutput output, ModelExpression model)
     {
-        var modelAttribute = model.ModelExplorer.GetAttribute<DateRangePickerAttribute>();
+        var modelAttribute = model.ModelExplorer.GetAttribute<DateRangePickerAttribute>()!;
 
         var pickerId = modelAttribute.PickerId;
 
@@ -214,16 +214,16 @@ public class AbpDynamicFormTagHelperService : AbpTagHelperService<AbpDynamicForm
             abpDateRangeInputTagHelper.AspForStart = model;
 
             var otherModelExists = TryToGetOtherDateModel(model, pickerId, out var otherModel);
-            if (otherModelExists && otherModel.GetAttribute<DateRangePickerAttribute>().IsEnd)
+            if (otherModelExists && otherModel!.GetAttribute<DateRangePickerAttribute>()!.IsEnd)
             {
-                abpDateRangeInputTagHelper.AspForEnd = ModelExplorerToModelExpressionConverter(otherModel);
+                abpDateRangeInputTagHelper.AspForEnd = ModelExplorerToModelExpressionConverter(otherModel!);
             }
         }
 
         return abpDateRangeInputTagHelper;
     }
 
-    private bool TryToGetOtherDateModel(ModelExpression model, string pickerId, out ModelExplorer otherModel)
+    private bool TryToGetOtherDateModel(ModelExpression model, string pickerId, out ModelExplorer? otherModel)
     {
         otherModel = TagHelper.Model.ModelExplorer.Properties.SingleOrDefault(x => x != model.ModelExplorer && x.GetAttribute<DateRangePickerAttribute>()?.PickerId == pickerId);
         return otherModel != null;
@@ -266,7 +266,7 @@ public class AbpDynamicFormTagHelperService : AbpTagHelperService<AbpDynamicForm
 
     protected virtual AbpTagHelper GetAbpRadioInputTagHelper(ModelExpression model)
     {
-        var radioButtonAttribute = model.ModelExplorer.GetAttribute<AbpRadioButton>();
+        var radioButtonAttribute = model.ModelExplorer.GetAttribute<AbpRadioButton>()!;
         var abpRadioInputTagHelper = _serviceProvider.GetRequiredService<AbpRadioInputTagHelper>();
         abpRadioInputTagHelper.AspFor = model;
         abpRadioInputTagHelper.AspItems = null;
@@ -356,7 +356,7 @@ public class AbpDynamicFormTagHelperService : AbpTagHelperService<AbpDynamicForm
         return type.ToString().StartsWith("System.Collections.Generic.IEnumerable`") || type.ToString().StartsWith("System.Collections.Generic.List`");
     }
 
-    protected virtual bool IsCsharpClassOrPrimitive(Type type)
+    protected virtual bool IsCsharpClassOrPrimitive(Type? type)
     {
         if (type == null)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpIdNameTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpIdNameTagHelper.cs
index d24e247abe..c83762a4a1 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpIdNameTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpIdNameTagHelper.cs
@@ -18,7 +18,7 @@ public class AbpIdNameTagHelper : AbpTagHelper
     public override int Order => -1000 - 1;
 
     [HtmlAttributeName("abp-id-name")]
-    public ModelExpression IdNameFor { get; set; }
+    public ModelExpression? IdNameFor { get; set; }
 
     private readonly MvcViewOptions _mvcViewOptions;
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpInputTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpInputTagHelper.cs
index 8c58e3c285..a426b50d33 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpInputTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpInputTagHelper.cs
@@ -6,11 +6,11 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Form;
 
 public class AbpInputTagHelper : AbpTagHelper<AbpInputTagHelper, AbpInputTagHelperService>
 {
-    public ModelExpression AspFor { get; set; }
+    public ModelExpression AspFor { get; set; } = default!;
 
-    public string Label { get; set; }
+    public string? Label { get; set; }
 
-    public string LabelTooltip { get; set; }
+    public string? LabelTooltip { get; set; }
 
     public string LabelTooltipIcon { get; set; } = "bi-info-circle";
 
@@ -19,7 +19,7 @@ public class AbpInputTagHelper : AbpTagHelper<AbpInputTagHelper, AbpInputTagHelp
     public bool LabelTooltipHtml  { get; set; } = false;
 
     [HtmlAttributeName("info")]
-    public string InfoText { get; set; }
+    public string? InfoText { get; set; }
 
     [HtmlAttributeName("disabled")]
     public bool IsDisabled { get; set; } = false;
@@ -30,7 +30,7 @@ public class AbpInputTagHelper : AbpTagHelper<AbpInputTagHelper, AbpInputTagHelp
     public bool AutoFocus { get; set; }
 
     [HtmlAttributeName("type")]
-    public string InputTypeName { get; set; }
+    public string? InputTypeName { get; set; }
 
     public AbpFormControlSize Size { get; set; } = AbpFormControlSize.Default;
 
@@ -38,11 +38,11 @@ public class AbpInputTagHelper : AbpTagHelper<AbpInputTagHelper, AbpInputTagHelp
     public bool DisplayRequiredSymbol { get; set; } = true;
 
     [HtmlAttributeName("asp-format")]
-    public string Format { get; set; }
+    public string? Format { get; set; }
 
-    public string Name { get; set; }
+    public string? Name { get; set; }
 
-    public string Value { get; set; }
+    public string? Value { get; set; }
 
     public bool SuppressLabel { get; set; }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpInputTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpInputTagHelperService.cs
index d3469c77bf..981116aa9f 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpInputTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpInputTagHelperService.cs
@@ -397,7 +397,7 @@ public class AbpInputTagHelperService : AbpTagHelperService<AbpInputTagHelper>
         }
     }
 
-    protected virtual TextArea TryGetTextAreaAttribute(TagHelperOutput output)
+    protected virtual TextArea? TryGetTextAreaAttribute(TagHelperOutput output)
     {
         var textAreaAttribute = TagHelper.AspFor.ModelExplorer.GetAttribute<TextArea>();
 
@@ -479,14 +479,14 @@ public class AbpInputTagHelperService : AbpTagHelperService<AbpInputTagHelper>
 
     protected virtual bool IsOutputHidden(TagHelperOutput inputTag)
     {
-        return inputTag.Attributes.Any(a => a.Name.ToLowerInvariant() == "type" && a.Value.ToString().ToLowerInvariant() == "hidden");
+        return inputTag.Attributes.Any(a => a.Name.ToLowerInvariant() == "type" && a.Value.ToString()!.ToLowerInvariant() == "hidden");
     }
 
     protected virtual string GetIdAttributeValue(TagHelperOutput inputTag)
     {
         var idAttr = inputTag.Attributes.FirstOrDefault(a => a.Name == "id");
 
-        return idAttr != null ? idAttr.Value.ToString() : string.Empty;
+        return idAttr != null ? idAttr.Value.ToString()! : string.Empty;
     }
 
     protected virtual string GetIdAttributeAsString(TagHelperOutput inputTag)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpRadioInputTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpRadioInputTagHelper.cs
index e076b13b04..0135d136ba 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpRadioInputTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpRadioInputTagHelper.cs
@@ -8,15 +8,15 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Form;
 [HtmlTargetElement("abp-radio")]
 public class AbpRadioInputTagHelper : AbpTagHelper<AbpRadioInputTagHelper, AbpRadioInputTagHelperService>
 {
-    public ModelExpression AspFor { get; set; }
+    public ModelExpression AspFor { get; set; } = default!;
 
-    public string Label { get; set; }
+    public string? Label { get; set; }
 
     public bool? Inline { get; set; }
 
     public bool? Disabled { get; set; }
 
-    public IEnumerable<SelectListItem> AspItems { get; set; }
+    public IEnumerable<SelectListItem>? AspItems { get; set; }
 
     public AbpRadioInputTagHelper(AbpRadioInputTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpRadioInputTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpRadioInputTagHelperService.cs
index ea4bacb224..58e5300cbf 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpRadioInputTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpRadioInputTagHelperService.cs
@@ -113,12 +113,12 @@ public class AbpRadioInputTagHelperService : AbpTagHelperService<AbpRadioInputTa
         var localizer = _tagHelperLocalizer.GetLocalizerOrNull(explorer);
 
         var selectItems = explorer.Metadata.IsEnum ? explorer.ModelType.GetTypeInfo().GetMembers(BindingFlags.Public | BindingFlags.Static)
-            .Select((t, i) => new SelectListItem { Value = i.ToString(), Text = GetLocalizedPropertyName(localizer, explorer.ModelType, t.Name) }).ToList() : null;
+            .Select((t, i) => new SelectListItem { Value = i.ToString(), Text = GetLocalizedPropertyName(localizer, explorer.ModelType, t.Name) }).ToList() : new List<SelectListItem>();
 
         return selectItems;
     }
 
-    protected virtual string GetLocalizedPropertyName(IStringLocalizer localizer, Type enumType, string propertyName)
+    protected virtual string GetLocalizedPropertyName(IStringLocalizer? localizer, Type enumType, string propertyName)
     {
         if (localizer == null)
         {
@@ -159,7 +159,7 @@ public class AbpRadioInputTagHelperService : AbpTagHelperService<AbpRadioInputTa
         }
     }
 
-    protected virtual string GetSelectedValue(TagHelperContext context, TagHelperOutput output)
+    protected virtual string? GetSelectedValue(TagHelperContext context, TagHelperOutput output)
     {
         if (TagHelper.AspFor.ModelExplorer.Metadata.IsEnum)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelper.cs
index fd4c42fcff..7d11f69636 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelper.cs
@@ -8,41 +8,41 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Form;
 [OutputElementHint("select")]
 public class AbpSelectTagHelper : AbpTagHelper<AbpSelectTagHelper, AbpSelectTagHelperService>
 {
-    public ModelExpression AspFor { get; set; }
+    public ModelExpression AspFor { get; set; } = default!;
 
-    public string Label { get; set; }
+    public string? Label { get; set; }
 
     public bool SuppressLabel { get; set; }
 
-    public IEnumerable<SelectListItem> AspItems { get; set; }
+    public IEnumerable<SelectListItem>? AspItems { get; set; }
 
     public AbpFormControlSize Size { get; set; } = AbpFormControlSize.Default;
 
     [HtmlAttributeName("info")]
-    public string InfoText { get; set; }
+    public string? InfoText { get; set; }
 
     [HtmlAttributeName("required-symbol")]
     public bool DisplayRequiredSymbol { get; set; } = true;
 
-    public string AutocompleteApiUrl { get; set; }
+    public string? AutocompleteApiUrl { get; set; }
 
-    public string AutocompleteItemsPropertyName { get; set; }
+    public string? AutocompleteItemsPropertyName { get; set; }
 
-    public string AutocompleteDisplayPropertyName { get; set; }
+    public string? AutocompleteDisplayPropertyName { get; set; }
 
-    public string AutocompleteValuePropertyName { get; set; }
+    public string? AutocompleteValuePropertyName { get; set; }
 
-    public string AutocompleteFilterParamName { get; set; }
+    public string? AutocompleteFilterParamName { get; set; }
 
-    public string AutocompleteSelectedItemName { get; set; }
+    public string? AutocompleteSelectedItemName { get; set; }
 
-    public string AutocompleteSelectedItemValue { get; set; }
+    public string? AutocompleteSelectedItemValue { get; set; }
     
-    public string AutocompleteParentSelector { get; set; }
+    public string? AutocompleteParentSelector { get; set; }
 
-    public string AllowClear { get; set; }
+    public string? AllowClear { get; set; }
 
-    public string Placeholder { get; set; }
+    public string? Placeholder { get; set; }
 
     [HtmlAttributeName("floating-label")]
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelperService.cs
index 90268b7429..0edc8f1008 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/AbpSelectTagHelperService.cs
@@ -266,7 +266,7 @@ public class AbpSelectTagHelperService : AbpTagHelperService<AbpSelectTagHelper>
 
         if (isNullableType)
         {
-            enumType = Nullable.GetUnderlyingType(explorer.ModelType);
+            enumType = Nullable.GetUnderlyingType(explorer.ModelType)!;
             selectItems.Add(new SelectListItem());
         }
 
@@ -279,7 +279,7 @@ public class AbpSelectTagHelperService : AbpTagHelperService<AbpSelectTagHelper>
                 {
                     containerLocalizer,
                     _stringLocalizerFactory.CreateDefaultOrNull()
-                });
+                }!);
             selectItems.Add(new SelectListItem
             {
                 Value = enumValue.ToString(),
@@ -386,7 +386,7 @@ public class AbpSelectTagHelperService : AbpTagHelperService<AbpSelectTagHelper>
     {
         var idAttr = inputTag.Attributes.FirstOrDefault(a => a.Name == "id");
 
-        return idAttr != null ? idAttr.Value.ToString() : string.Empty;
+        return idAttr != null ? idAttr.Value.ToString()! : string.Empty;
     }
 
     protected virtual string GetIdAttributeAsString(TagHelperOutput inputTag)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerBaseTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerBaseTagHelper.cs
index 7f9c34fb7a..fed2981613 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerBaseTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerBaseTagHelper.cs
@@ -11,9 +11,9 @@ public abstract class
 {
     private IAbpDatePickerOptions _abpDatePickerOptionsImplementation;
 
-    public string Label { get; set; }
+    public string? Label { get; set; }
 
-    public string LabelTooltip { get; set; }
+    public string? LabelTooltip { get; set; }
 
     public string LabelTooltipIcon { get; set; } = "bi-info-circle";
 
@@ -22,7 +22,7 @@ public abstract class
     public bool LabelTooltipHtml { get; set; } = false;
 
     [HtmlAttributeName("info")] 
-    public string InfoText { get; set; }
+    public string? InfoText { get; set; }
 
     [HtmlAttributeName("disabled")] 
     public bool IsDisabled { get; set; } = false;
@@ -37,9 +37,9 @@ public abstract class
     [HtmlAttributeName("required-symbol")] 
     public bool DisplayRequiredSymbol { get; set; } = true;
 
-    public string Name { get; set; }
+    public string? Name { get; set; }
 
-    public string Value { get; set; }
+    public string? Value { get; set; }
 
     public bool SuppressLabel { get; set; }
 
@@ -53,7 +53,7 @@ public abstract class
         _abpDatePickerOptionsImplementation = options;
     }
 
-    public string PickerId {
+    public string? PickerId {
         get => _abpDatePickerOptionsImplementation.PickerId;
         set => _abpDatePickerOptionsImplementation.PickerId = value;
     }
@@ -68,7 +68,7 @@ public abstract class
         set => _abpDatePickerOptionsImplementation.MaxDate = value;
     }
 
-    public object MaxSpan {
+    public object? MaxSpan {
         get => _abpDatePickerOptionsImplementation.MaxSpan;
         set => _abpDatePickerOptionsImplementation.MaxSpan = value;
     }
@@ -113,7 +113,7 @@ public abstract class
         set => _abpDatePickerOptionsImplementation.TimePickerSeconds = value;
     }
 
-    public List<AbpDatePickerRange> Ranges {
+    public List<AbpDatePickerRange>? Ranges {
         get => _abpDatePickerOptionsImplementation.Ranges;
         set => _abpDatePickerOptionsImplementation.Ranges = value;
     }
@@ -138,27 +138,27 @@ public abstract class
         set => _abpDatePickerOptionsImplementation.Drops = value;
     }
 
-    public string ButtonClasses {
+    public string? ButtonClasses {
         get => _abpDatePickerOptionsImplementation.ButtonClasses;
         set => _abpDatePickerOptionsImplementation.ButtonClasses = value;
     }
 
-    public string TodayButtonClasses {
+    public string? TodayButtonClasses {
         get => _abpDatePickerOptionsImplementation.TodayButtonClasses;
         set => _abpDatePickerOptionsImplementation.TodayButtonClasses = value;
     }
 
-    public string ApplyButtonClasses {
+    public string? ApplyButtonClasses {
         get => _abpDatePickerOptionsImplementation.ApplyButtonClasses;
         set => _abpDatePickerOptionsImplementation.ApplyButtonClasses = value;
     }
 
-    public string ClearButtonClasses {
+    public string? ClearButtonClasses {
         get => _abpDatePickerOptionsImplementation.ClearButtonClasses;
         set => _abpDatePickerOptionsImplementation.ClearButtonClasses = value;
     }
 
-    public object Locale {
+    public object? Locale {
         get => _abpDatePickerOptionsImplementation.Locale;
         set => _abpDatePickerOptionsImplementation.Locale = value;
     }
@@ -178,12 +178,12 @@ public abstract class
         set => _abpDatePickerOptionsImplementation.AutoUpdateInput = value;
     }
 
-    public string ParentEl {
+    public string? ParentEl {
         get => _abpDatePickerOptionsImplementation.ParentEl;
         set => _abpDatePickerOptionsImplementation.ParentEl = value;
     }
 
-    public string DateFormat {
+    public string? DateFormat {
         get => _abpDatePickerOptionsImplementation.DateFormat;
         set => _abpDatePickerOptionsImplementation.DateFormat = value;
     }
@@ -213,7 +213,7 @@ public abstract class
         set => _abpDatePickerOptionsImplementation.IsIso = value;
     }
 
-    public object Options {
+    public object? Options {
         get => _abpDatePickerOptionsImplementation.Options;
         set => _abpDatePickerOptionsImplementation.Options = value;
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerBaseTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerBaseTagHelperService.cs
index 92bb48b974..024fd4dd45 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerBaseTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerBaseTagHelperService.cs
@@ -46,7 +46,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
                 return string.Empty;
             }
         },
-        {typeof(DateTime?), o => ((DateTime?) o)?.ToString("O")},
+        {typeof(DateTime?), o => ((DateTime?) o)?.ToString("O")!},
         {
             typeof(DateTimeOffset), o =>
             {
@@ -58,7 +58,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
                 return string.Empty;
             }
         },
-        {typeof(DateTimeOffset?), o => ((DateTimeOffset?) o)?.ToString("O")}
+        {typeof(DateTimeOffset?), o => ((DateTimeOffset?) o)?.ToString("O")!}
     };
 
     protected readonly IJsonSerializer JsonSerializer;
@@ -85,12 +85,12 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
         InputTagHelper = new InputTagHelper(Generator) { InputTypeName = "text" };
     }
 
-    protected virtual T GetAttribute<T>() where T : Attribute
+    protected virtual T? GetAttribute<T>() where T : Attribute
     {
         return GetAttributeAndModelExpression<T>(out _);
     }
 
-    protected abstract T GetAttributeAndModelExpression<T>(out ModelExpression modelExpression) where T : Attribute;
+    protected abstract T? GetAttributeAndModelExpression<T>(out ModelExpression? modelExpression) where T : Attribute;
 
 
     public async override Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
@@ -118,7 +118,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
         var optionsAttribute = GetAttributeAndModelExpression<DatePickerOptionsAttribute>(out var modelExpression);
         if (optionsAttribute != null)
         {
-            TagHelper.SetDatePickerOptions(optionsAttribute.GetDatePickerOptions(modelExpression.ModelExplorer));
+            TagHelper.SetDatePickerOptions(optionsAttribute.GetDatePickerOptions(modelExpression!.ModelExplorer)!);
         }
 
         // Open and close button
@@ -250,7 +250,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
         return string.Empty;
     }
 
-    protected TagHelperAttributeList ConvertDatePickerOptionsToAttributeList(IAbpDatePickerOptions options)
+    protected TagHelperAttributeList ConvertDatePickerOptionsToAttributeList(IAbpDatePickerOptions? options)
     {
         var attrList = new TagHelperAttributeList();
 
@@ -281,7 +281,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
 
         if (options.ShowDropdowns == false)
         {
-            attrList.Add("data-show-dropdowns", options.ShowDropdowns.ToString().ToLowerInvariant());
+            attrList.Add("data-show-dropdowns", options.ShowDropdowns.ToString()!.ToLowerInvariant());
         }
 
         if (options.MinYear != null)
@@ -306,7 +306,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
 
         if (options.TimePicker != null)
         {
-            attrList.Add("data-time-picker", options.TimePicker.ToString().ToLowerInvariant());
+            attrList.Add("data-time-picker", options.TimePicker.ToString()!.ToLowerInvariant());
         }
 
         if (options.TimePickerIncrement != null)
@@ -316,12 +316,12 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
 
         if (options.TimePicker24Hour != null)
         {
-            attrList.Add("data-time-picker24-hour", options.TimePicker24Hour.ToString().ToLowerInvariant());
+            attrList.Add("data-time-picker24-hour", options.TimePicker24Hour.ToString()!.ToLowerInvariant());
         }
 
         if (options.TimePickerSeconds != null)
         {
-            attrList.Add("data-time-picker-seconds", options.TimePickerSeconds.ToString().ToLowerInvariant());
+            attrList.Add("data-time-picker-seconds", options.TimePickerSeconds.ToString()!.ToLowerInvariant());
         }
 
         if (options.Opens != AbpDatePickerOpens.Center)
@@ -356,17 +356,17 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
 
         if (options.AutoApply != null)
         {
-            attrList.Add("data-auto-apply", options.AutoApply.ToString().ToLowerInvariant());
+            attrList.Add("data-auto-apply", options.AutoApply.ToString()!.ToLowerInvariant());
         }
 
         if (options.LinkedCalendars != null)
         {
-            attrList.Add("data-linked-calendars", options.LinkedCalendars.ToString().ToLowerInvariant());
+            attrList.Add("data-linked-calendars", options.LinkedCalendars.ToString()!.ToLowerInvariant());
         }
 
         if (options.AutoUpdateInput != null)
         {
-            attrList.Add("data-auto-update-input", options.AutoUpdateInput.ToString().ToLowerInvariant());
+            attrList.Add("data-auto-update-input", options.AutoUpdateInput.ToString()!.ToLowerInvariant());
         }
 
         if (!options.ParentEl.IsNullOrEmpty())
@@ -388,12 +388,12 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
 
         if(options.AlwaysShowCalendars != null)
         {
-            attrList.Add("data-always-show-calendars", options.AlwaysShowCalendars.ToString().ToLowerInvariant());
+            attrList.Add("data-always-show-calendars", options.AlwaysShowCalendars.ToString()!.ToLowerInvariant());
         }
 
         if(options.ShowCustomRangeLabel == false)
         {
-            attrList.Add("data-show-custom-range-label", options.ShowCustomRangeLabel.ToString().ToLowerInvariant());
+            attrList.Add("data-show-custom-range-label", options.ShowCustomRangeLabel.ToString()!.ToLowerInvariant());
         }
 
         if(options.Options != null)
@@ -403,12 +403,12 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
 
         if (options.IsUtc != null)
         {
-            attrList.Add("data-is-utc", options.IsUtc.ToString().ToLowerInvariant());
+            attrList.Add("data-is-utc", options.IsUtc.ToString()!.ToLowerInvariant());
         }
 
         if (options.IsIso != null)
         {
-            attrList.Add("data-is-iso", options.IsIso.ToString().ToLowerInvariant());
+            attrList.Add("data-is-iso", options.IsIso.ToString()!.ToLowerInvariant());
         }
 
         if (!options.PickerId.IsNullOrWhiteSpace())
@@ -481,7 +481,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
         }
 
         string text;
-        ModelExplorer modelExplorer = null;
+        ModelExplorer? modelExplorer = null;
 
         if (!string.IsNullOrEmpty(TagHelper.InfoText))
         {
@@ -492,7 +492,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
             var infoAttribute = GetAttributeAndModelExpression<InputInfoText>(out var modelExpression);
             if (infoAttribute != null)
             {
-                modelExplorer = modelExpression.ModelExplorer;
+                modelExplorer = modelExpression!.ModelExplorer;
                 text = infoAttribute.Text;
             }
             else
@@ -502,7 +502,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
         }
 
         var idAttr = inputTag.Attributes.FirstOrDefault(a => a.Name == "id");
-        modelExplorer ??= GetModelExpression().ModelExplorer;
+        modelExplorer ??= GetModelExpression()!.ModelExplorer;
         var localizedText = TagHelperLocalizer.GetLocalizedText(text, modelExplorer);
 
         var div = new TagBuilder("div");
@@ -553,7 +553,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
     {
         var idAttr = inputTag.Attributes.FirstOrDefault(a => a.Name == "id");
 
-        return idAttr != null ? idAttr.Value.ToString() : string.Empty;
+        return idAttr != null ? idAttr.Value.ToString()! : string.Empty;
     }
 
     protected virtual string GetRequiredSymbol(TagHelperContext context, TagHelperOutput output)
@@ -568,7 +568,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
         return GetAttribute<RequiredAttribute>() != null || isHaveRequiredAttribute ? "<span> * </span>" : "";
     }
 
-    protected abstract ModelExpression GetModelExpression();
+    protected abstract ModelExpression? GetModelExpression();
 
     protected virtual async Task<string> GetLabelAsHtmlUsingTagHelperAsync(TagHelperContext context,
         TagHelperOutput output)
@@ -651,7 +651,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
 
         if (infoAttribute != null)
         {
-            return TagHelperLocalizer.GetLocalizedText(infoAttribute.Text, modelExpression.ModelExplorer);
+            return TagHelperLocalizer.GetLocalizedText(infoAttribute.Text, modelExpression!.ModelExplorer);
         }
 
         return string.Empty;
@@ -669,7 +669,7 @@ public abstract class AbpDatePickerBaseTagHelperService<TTagHelper> : AbpTagHelp
         if (attribute != null)
         {
             var placeholderLocalized =
-                TagHelperLocalizer.GetLocalizedText(attribute.Value, modelExpression.ModelExplorer);
+                TagHelperLocalizer.GetLocalizedText(attribute.Value, modelExpression!.ModelExplorer);
 
             inputTagHelperOutput.Attributes.Add("placeholder", placeholderLocalized);
         }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerOptions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerOptions.cs
index 15b4e2003d..2007a8a669 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerOptions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerOptions.cs
@@ -5,10 +5,10 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Form.DatePicker;
 
 public class AbpDatePickerOptions : IAbpDatePickerOptions
 {
-    public string PickerId { get; set; }
+    public string? PickerId { get; set; }
     public DateTime? MinDate { get; set; }
     public DateTime? MaxDate { get; set; }
-    public object MaxSpan { get; set; }
+    public object? MaxSpan { get; set; }
     public bool? ShowDropdowns { get; set; }
     public int? MinYear { get; set; }
     public int? MaxYear { get; set; }
@@ -17,25 +17,25 @@ public class AbpDatePickerOptions : IAbpDatePickerOptions
     public int? TimePickerIncrement { get; set; }
     public bool? TimePicker24Hour { get; set; }
     public bool? TimePickerSeconds { get; set; }
-    public List<AbpDatePickerRange> Ranges { get; set; }
+    public List<AbpDatePickerRange>? Ranges { get; set; }
     public bool? ShowCustomRangeLabel { get; set; }
     public bool? AlwaysShowCalendars { get; set; }
     public AbpDatePickerOpens Opens { get; set; } = AbpDatePickerOpens.Center;
     public AbpDatePickerDrops Drops { get; set; } = AbpDatePickerDrops.Down;
-    public string ButtonClasses { get; set; }
-    public string TodayButtonClasses { get; set; }
-    public string ApplyButtonClasses { get; set; }
-    public string ClearButtonClasses { get; set; }
-    public object Locale { get; set; }
+    public string? ButtonClasses { get; set; }
+    public string? TodayButtonClasses { get; set; }
+    public string? ApplyButtonClasses { get; set; }
+    public string? ClearButtonClasses { get; set; }
+    public object? Locale { get; set; }
     public bool? AutoApply { get; set; }
     public bool? LinkedCalendars { get; set; }
     public bool? AutoUpdateInput { get; set; }
-    public string ParentEl { get; set; }
-    public string DateFormat { get; set; }
+    public string? ParentEl { get; set; }
+    public string? DateFormat { get; set; }
     public bool OpenButton { get; set; } = true;
     public bool ClearButton { get; set; } = true;
     public bool SingleOpenAndClearButton { get; set; } = true;
     public bool? IsUtc { get; set; }
     public bool? IsIso { get; set; }
-    public object Options { get; set; }
+    public object? Options { get; set; }
 }
\ No newline at end of file
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerRange.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerRange.cs
index eea3d2ad31..3dfee14018 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerRange.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerRange.cs
@@ -6,7 +6,7 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Form.DatePicker;
 public class AbpDatePickerRange
 {
     private readonly List<string> _dates = new List<string>();
-    public string Label { get; set; }
+    public string Label { get; set; } = default!;
     public IReadOnlyList<string> Dates => _dates;
 
     public AbpDatePickerRange()
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerTagHelper.cs
index 8426b0071b..519952d21e 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerTagHelper.cs
@@ -7,8 +7,7 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Form.DatePicker;
 [HtmlTargetElement("abp-date-picker", TagStructure = TagStructure.NormalOrSelfClosing)]
 public class AbpDatePickerTagHelper : AbpDatePickerBaseTagHelper<AbpDatePickerTagHelper>
 {
-    [CanBeNull] 
-    public ModelExpression AspFor { get; set; }
+    public ModelExpression? AspFor { get; set; }
     
     public AbpDatePickerTagHelper(AbpDatePickerTagHelperService service) : base(service)
     {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerTagHelperService.cs
index 727ab1a239..d135d28667 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDatePickerTagHelperService.cs
@@ -19,19 +19,17 @@ public class AbpDatePickerTagHelperService : AbpDatePickerBaseTagHelperService<A
 
     }
 
-    protected override TagHelperOutput TagHelperOutput { get; set; }
+    protected override TagHelperOutput TagHelperOutput { get; set; } = default!;
 
-    [CanBeNull]
-    protected virtual InputTagHelper DateTagHelper { get; set; }
+    protected virtual InputTagHelper? DateTagHelper { get; set; }
 
-    [CanBeNull]
-    protected virtual TagHelperOutput DateTagHelperOutput { get; set; }
+    protected virtual TagHelperOutput? DateTagHelperOutput { get; set; }
     protected override string GetPropertyName()
     {
         return TagHelper.AspFor?.Name ?? string.Empty;
     }
 
-    protected override T GetAttributeAndModelExpression<T>(out ModelExpression modelExpression)
+    protected override T? GetAttributeAndModelExpression<T>(out ModelExpression? modelExpression) where T : class
     {
         modelExpression = TagHelper.AspFor;
         return modelExpression?.ModelExplorer.GetAttribute<T>();
@@ -74,7 +72,7 @@ public class AbpDatePickerTagHelperService : AbpDatePickerBaseTagHelperService<A
         }
     }
 
-    protected override ModelExpression GetModelExpression()
+    protected override ModelExpression? GetModelExpression()
     {
         return TagHelper.AspFor;
     }
@@ -86,6 +84,6 @@ public class AbpDatePickerTagHelperService : AbpDatePickerBaseTagHelperService<A
 
     protected override string GetExtraInputHtml(TagHelperContext context, TagHelperOutput output)
     {
-        return DateTagHelperOutput?.Render(Encoder);
+        return DateTagHelperOutput?.Render(Encoder)!;
     }
 }
\ No newline at end of file
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDateRangePickerTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDateRangePickerTagHelper.cs
index bfd1e354f6..e2f249bf28 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDateRangePickerTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDateRangePickerTagHelper.cs
@@ -7,11 +7,9 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Form.DatePicker;
 [HtmlTargetElement("abp-date-range-picker", TagStructure = TagStructure.NormalOrSelfClosing)]
 public class AbpDateRangePickerTagHelper : AbpDatePickerBaseTagHelper<AbpDateRangePickerTagHelper>
 {
-    [CanBeNull] 
-    public ModelExpression AspForStart { get; set; }
+    public ModelExpression? AspForStart { get; set; }
 
-    [CanBeNull] 
-    public ModelExpression AspForEnd { get; set; }
+    public ModelExpression? AspForEnd { get; set; }
 
     public AbpDateRangePickerTagHelper(AbpDateRangePickerTagHelperService tagHelperService) :
         base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDateRangePickerTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDateRangePickerTagHelperService.cs
index 45a083b789..48eeb5ba94 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDateRangePickerTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/AbpDateRangePickerTagHelperService.cs
@@ -25,7 +25,7 @@ public class AbpDateRangePickerTagHelperService : AbpDatePickerBaseTagHelperServ
 
     protected override string TagName { get; set; } = "abp-date-range-picker";
 
-    protected override T GetAttributeAndModelExpression<T>(out ModelExpression modelExpression)
+    protected override T? GetAttributeAndModelExpression<T>(out ModelExpression? modelExpression) where T : class
     {
         modelExpression = new[] { TagHelper.AspForStart, TagHelper.AspForEnd }.FirstOrDefault(x => x?.ModelExplorer?.GetAttribute<T>() != null);
         return modelExpression?.ModelExplorer.GetAttribute<T>();
@@ -62,19 +62,15 @@ public class AbpDateRangePickerTagHelperService : AbpDatePickerBaseTagHelperServ
         await base.ProcessAsync(context, output);
     }
 
-    protected override TagHelperOutput TagHelperOutput { get; set; }
+    protected override TagHelperOutput TagHelperOutput { get; set; } = default!;
 
-    [CanBeNull]
-    protected virtual InputTagHelper StartDateTagHelper { get; set; }
+    protected virtual InputTagHelper? StartDateTagHelper { get; set; }
 
-    [CanBeNull]
-    protected virtual TagHelperOutput StartDateTagHelperOutput { get; set; }
+    protected virtual TagHelperOutput? StartDateTagHelperOutput { get; set; }
 
-    [CanBeNull]
-    protected virtual InputTagHelper EndDateTagHelper { get; set; }
+    protected virtual InputTagHelper? EndDateTagHelper { get; set; }
 
-    [CanBeNull]
-    protected virtual TagHelperOutput EndDateTagHelperOutput { get; set; }
+    protected virtual TagHelperOutput? EndDateTagHelperOutput { get; set; }
 
     protected override string GetPropertyName()
     {
@@ -108,7 +104,7 @@ public class AbpDateRangePickerTagHelperService : AbpDatePickerBaseTagHelperServ
         return StartDateTagHelperOutput?.Render(Encoder) + EndDateTagHelperOutput?.Render(Encoder);
     }
 
-    protected override ModelExpression GetModelExpression()
+    protected override ModelExpression? GetModelExpression()
     {
         return TagHelper.AspForStart;
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/DatePickerOptionsAttribute.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/DatePickerOptionsAttribute.cs
index 9cff72aa23..235801bd78 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/DatePickerOptionsAttribute.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/DatePickerOptionsAttribute.cs
@@ -14,7 +14,7 @@ public class DatePickerOptionsAttribute : Attribute
         DatePickerOptionsPropertyName = datePickerOptionsPropertyName;
     }
     
-    public IAbpDatePickerOptions GetDatePickerOptions(ModelExplorer explorer)
+    public IAbpDatePickerOptions? GetDatePickerOptions(ModelExplorer explorer)
     {
         var properties = explorer.Container.Properties.Where(p => p.Metadata.PropertyName != null && p.Metadata.PropertyName.Equals(DatePickerOptionsPropertyName)).ToList();
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/IAbpDatePickerOptions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/IAbpDatePickerOptions.cs
index 118c409da9..5244a844fa 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/IAbpDatePickerOptions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/DatePicker/IAbpDatePickerOptions.cs
@@ -6,7 +6,7 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Form.DatePicker;
 
 public interface IAbpDatePickerOptions
 {
-    public string PickerId { get; set; }
+    public string? PickerId { get; set; }
 
     /// <summary>
     /// Min date allowed
@@ -21,7 +21,7 @@ public interface IAbpDatePickerOptions
     /// <summary>
     /// The maximum span between the selected start and end dates. Can have any property you can add to a moment object (i.e. days, months)
     /// </summary>
-    object MaxSpan { get; set; }
+    object? MaxSpan { get; set; }
 
     /// <summary>
     /// Show year and month select boxes above calendars to jump to a specific month and year.
@@ -66,7 +66,7 @@ public interface IAbpDatePickerOptions
     /// <summary>
     /// Set predefined date ranges the user can select from. Each key is the label for the range, and its value an array with two dates representing the bounds of the range.
     /// </summary>
-    List<AbpDatePickerRange> Ranges { get; set; }
+    List<AbpDatePickerRange>? Ranges { get; set; }
 
     /// <summary>
     /// Displays "Custom Range" at the end of the list of predefined ranges, when the ranges option is used. This option will be highlighted whenever the current date range selection does not match one of the predefined ranges. Clicking it will display the calendars to select a new range.
@@ -91,32 +91,28 @@ public interface IAbpDatePickerOptions
     /// <summary>
     /// CSS class names that will be added to both the today, clear, and apply buttons.
     /// </summary>
-    [CanBeNull]
-    string ButtonClasses { get; set; }
+    string? ButtonClasses { get; set; }
 
     /// <summary>
     /// CSS class names that will be added only to the today button.
     /// </summary>
-    [CanBeNull]
-    string TodayButtonClasses { get; set; }
+    string? TodayButtonClasses { get; set; }
     
     /// <summary>
     /// CSS class names that will be added only to the apply button.
     /// </summary>
-    [CanBeNull]
-    string ApplyButtonClasses { get; set; }
+    string? ApplyButtonClasses { get; set; }
 
     /// <summary>
     /// CSS class names that will be added only to the clear button.
     /// </summary>
-    [CanBeNull]
-    string ClearButtonClasses { get; set; }
+    string? ClearButtonClasses { get; set; }
 
     /// <summary>
     /// Allows you to provide localized strings for buttons and labels, customize the date format, and change the first day of week for the calendars.
     /// </summary>
     [CanBeNull]
-    object Locale { get; set; }
+    object? Locale { get; set; }
 
     /// <summary>
     /// Hide the apply button, and automatically apply a new date range as soon as two dates are clicked.
@@ -136,11 +132,9 @@ public interface IAbpDatePickerOptions
     /// <summary>
     /// jQuery selector of the parent element that the date range picker will be added to, if not provided this will be 'body'
     /// </summary>
-    [CanBeNull]
-    string ParentEl { get; set; }
+    string? ParentEl { get; set; }
     
-    [CanBeNull]
-    string DateFormat { get; set; }
+    string? DateFormat { get; set; }
 
     bool OpenButton { get; set; }
 
@@ -155,6 +149,5 @@ public interface IAbpDatePickerOptions
     /// <summary>
     /// Other non-mapped attributes will be automatically added to the input element as is.
     /// </summary>
-    [CanBeNull]
-    object Options { get; set; }
+    object? Options { get; set; }
 }
\ No newline at end of file
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/FormGroupItem.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/FormGroupItem.cs
index b56d68abdf..82b82d50ac 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/FormGroupItem.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/FormGroupItem.cs
@@ -2,9 +2,9 @@
 
 public class FormGroupItem
 {
-    public string HtmlContent { get; set; }
+    public string HtmlContent { get; set; } = default!;
 
     public int Order { get; set; }
 
-    public string PropertyName { get; set; }
+    public string PropertyName { get; set; } = default!;
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/SelectItems.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/SelectItems.cs
index fc64858a56..7f9e530eb4 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/SelectItems.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Form/SelectItems.cs
@@ -16,9 +16,9 @@ public class SelectItems : Attribute
         ItemsListPropertyName = itemsListPropertyName;
     }
 
-    public IEnumerable<SelectListItem> GetItems(ModelExplorer explorer)
+    public IEnumerable<SelectListItem>? GetItems(ModelExplorer explorer)
     {
-        var properties = explorer.Container.Properties.Where(p => p.Metadata.PropertyName.Equals(ItemsListPropertyName)).ToList();
+        var properties = explorer.Container.Properties.Where(p => p.Metadata.PropertyName!.Equals(ItemsListPropertyName)).ToList();
 
         while (properties.Count == 0)
         {
@@ -28,10 +28,10 @@ public class SelectItems : Attribute
                 return null;
             }
 
-            properties = explorer.Container.Properties.Where(p => p.Metadata.PropertyName.Equals(ItemsListPropertyName)).ToList();
+            properties = explorer.Container.Properties.Where(p => p.Metadata.PropertyName!.Equals(ItemsListPropertyName)).ToList();
         }
 
-        var selectItems = (properties.First().Model as IEnumerable<SelectListItem>).ToList();
+        var selectItems = (properties.First().Model as IEnumerable<SelectListItem>)!.ToList();
 
         return selectItems;
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/IAbpTagHelperLocalizer.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/IAbpTagHelperLocalizer.cs
index ca3ae84de3..f19f1dd8d7 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/IAbpTagHelperLocalizer.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/IAbpTagHelperLocalizer.cs
@@ -10,7 +10,7 @@ public interface IAbpTagHelperLocalizer : ITransientDependency
 {
     string GetLocalizedText(string text, ModelExplorer explorer);
 
-    IStringLocalizer GetLocalizerOrNull(ModelExplorer explorer);
+    IStringLocalizer? GetLocalizerOrNull(ModelExplorer explorer);
 
-    IStringLocalizer GetLocalizerOrNull(Assembly assembly);
+    IStringLocalizer? GetLocalizerOrNull(Assembly assembly);
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/ListGroup/AbpListGroupItemTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/ListGroup/AbpListGroupItemTagHelper.cs
index 13ef2f4089..c116a2a980 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/ListGroup/AbpListGroupItemTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/ListGroup/AbpListGroupItemTagHelper.cs
@@ -6,7 +6,7 @@ public class AbpListGroupItemTagHelper : AbpTagHelper<AbpListGroupItemTagHelper,
 
     public bool? Disabled { get; set; }
 
-    public string Href { get; set; }
+    public string? Href { get; set; }
 
     public AbpListItemTagType TagType { get; set; } = AbpListItemTagType.Default;
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Modal/AbpModalHeaderTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Modal/AbpModalHeaderTagHelper.cs
index 44881ddb8c..832edd5774 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Modal/AbpModalHeaderTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Modal/AbpModalHeaderTagHelper.cs
@@ -2,7 +2,7 @@
 
 public class AbpModalHeaderTagHelper : AbpTagHelper<AbpModalHeaderTagHelper, AbpModalHeaderTagHelperService>
 {
-    public string Title { get; set; }
+    public string Title { get; set; } = default!;
 
     public AbpModalHeaderTagHelper(AbpModalHeaderTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Nav/AbpNavbarToggleTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Nav/AbpNavbarToggleTagHelper.cs
index 580bb29253..d0b4c5757f 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Nav/AbpNavbarToggleTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Nav/AbpNavbarToggleTagHelper.cs
@@ -2,7 +2,7 @@
 
 public class AbpNavbarToggleTagHelper : AbpTagHelper<AbpNavbarToggleTagHelper, AbpNavbarToggleTagHelperService>
 {
-    public string Id { get; set; }
+    public string? Id { get; set; }
 
     public AbpNavbarToggleTagHelper(AbpNavbarToggleTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Nav/NavItem.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Nav/NavItem.cs
index 00f494299b..e975207f09 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Nav/NavItem.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Nav/NavItem.cs
@@ -2,7 +2,7 @@
 
 public class NavItem
 {
-    public string Html { get; set; }
+    public string Html { get; set; } = default!;
 
     public bool Active { get; set; }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/AbpPaginationTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/AbpPaginationTagHelper.cs
index 35ec4ec65c..4c144bb92d 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/AbpPaginationTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/AbpPaginationTagHelper.cs
@@ -7,7 +7,7 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Pagination;
 [HtmlTargetElement("abp-paginator")]
 public class AbpPaginationTagHelper : AbpTagHelper<AbpPaginationTagHelper, AbpPaginationTagHelperService>
 {
-    public PagerModel Model { get; set; }
+    public PagerModel Model { get; set; } = default!;
 
     public bool? ShowInfo { get; set; }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/PageItem.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/PageItem.cs
index cf11fd6f0c..4f57d2b198 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/PageItem.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/PageItem.cs
@@ -16,7 +16,7 @@ public class PageItem
         IsGap = isGap;
     }
 
-    public override bool Equals(object obj)
+    public override bool Equals(object? obj)
     {
         if (!(obj is PageItem item))
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/PagerModel.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/PagerModel.cs
index 814863f0e8..b592af59a3 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/PagerModel.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Pagination/PagerModel.cs
@@ -25,13 +25,13 @@ public class PagerModel
 
     public int NextPage { get; set; }
 
-    public string Sort { get; set; }
+    public string? Sort { get; set; }
 
     public string PageUrl { get; set; }
 
     private const int MaxItemsCountToShowAllPages = 4;
 
-    public PagerModel(long totalCount, int shownItemsCount, int currentPage, int pageSize, string pageUrl, string sort = null)
+    public PagerModel(long totalCount, int shownItemsCount, int currentPage, int pageSize, string pageUrl, string? sort = null)
     {
         TotalItemsCount = totalCount;
         ShownItemsCount = shownItemsCount;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Popover/AbpPopoverTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Popover/AbpPopoverTagHelper.cs
index 695b2acafe..69331db6d3 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Popover/AbpPopoverTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Popover/AbpPopoverTagHelper.cs
@@ -20,15 +20,15 @@ public class AbpPopoverTagHelper : AbpTagHelper<AbpPopoverTagHelper, AbpPopoverT
 
     public bool? Hoverable { get; set; }
 
-    public string AbpPopover { get; set; }
+    public string? AbpPopover { get; set; }
 
-    public string AbpPopoverRight { get; set; }
+    public string? AbpPopoverRight { get; set; }
 
-    public string AbpPopoverLeft { get; set; }
+    public string? AbpPopoverLeft { get; set; }
 
-    public string AbpPopoverTop { get; set; }
+    public string? AbpPopoverTop { get; set; }
 
-    public string AbpPopoverBottom { get; set; }
+    public string? AbpPopoverBottom { get; set; }
 
     public AbpPopoverTagHelper(AbpPopoverTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Popover/AbpPopoverTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Popover/AbpPopoverTagHelperService.cs
index c4ee267f9f..2a1989f996 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Popover/AbpPopoverTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Popover/AbpPopoverTagHelperService.cs
@@ -124,15 +124,15 @@ public class AbpPopoverTagHelperService : AbpTagHelperService<AbpPopoverTagHelpe
         switch (GetDirectory())
         {
             case PopoverDirectory.Top:
-                return TagHelper.AbpPopoverTop;
+                return TagHelper.AbpPopoverTop!;
             case PopoverDirectory.Right:
-                return TagHelper.AbpPopoverRight;
+                return TagHelper.AbpPopoverRight!;
             case PopoverDirectory.Bottom:
-                return TagHelper.AbpPopoverBottom;
+                return TagHelper.AbpPopoverBottom!;
             case PopoverDirectory.Left:
-                return TagHelper.AbpPopoverLeft;
+                return TagHelper.AbpPopoverLeft!;
             default:
-                return TagHelper.AbpPopover;
+                return TagHelper.AbpPopover!;
         }
     }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabDropdownTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabDropdownTagHelper.cs
index 5bc1d221c8..72b416e958 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabDropdownTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabDropdownTagHelper.cs
@@ -5,9 +5,9 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Tab;
 [HtmlTargetElement("abp-tab-dropdown")]
 public class AbpTabDropdownTagHelper : AbpTagHelper<AbpTabDropdownTagHelper, AbpTabDropdownTagHelperService>
 {
-    public string Name { get; set; }
+    public string? Name { get; set; }
 
-    public string Title { get; set; }
+    public string Title { get; set; } = default!;
 
     public AbpTabDropdownTagHelper(AbpTabDropdownTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabLinkTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabLinkTagHelper.cs
index fa0d89eec0..281db5ca06 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabLinkTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabLinkTagHelper.cs
@@ -5,13 +5,13 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Tab;
 [HtmlTargetElement("abp-tab-link", TagStructure = TagStructure.WithoutEndTag)]
 public class AbpTabLinkTagHelper : AbpTagHelper<AbpTabLinkTagHelper, AbpTabLinkTagHelperService>
 {
-    public string Name { get; set; }
+    public string? Name { get; set; }
 
-    public string Title { get; set; }
+    public string Title { get; set; } = default!;
 
-    public string ParentDropdownName { get; set; }
+    public string? ParentDropdownName { get; set; }
 
-    public string Href { get; set; }
+    public string Href { get; set; } = default!;
 
     public AbpTabLinkTagHelper(AbpTabLinkTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabLinkTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabLinkTagHelperService.cs
index 5e0766c1af..2a7555021c 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabLinkTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabLinkTagHelperService.cs
@@ -16,7 +16,7 @@ public class AbpTabLinkTagHelperService : AbpTagHelperService<AbpTabLinkTagHelpe
 
         var tabHeaderItems = context.GetValue<List<TabItem>>(TabItems);
 
-        tabHeaderItems.Add(new TabItem(tabHeader, "", false, TagHelper.Name, TagHelper.ParentDropdownName, false));
+        tabHeaderItems.Add(new TabItem(tabHeader, "", false, TagHelper.Name!, TagHelper.ParentDropdownName, false));
 
         output.SuppressOutput();
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabTagHelper.cs
index 17f583e020..67bbbb3675 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabTagHelper.cs
@@ -5,13 +5,13 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Tab;
 [HtmlTargetElement("abp-tab")]
 public class AbpTabTagHelper : AbpTagHelper<AbpTabTagHelper, AbpTabTagHelperService>
 {
-    public string Name { get; set; }
+    public string? Name { get; set; }
 
-    public string Title { get; set; }
+    public string Title { get; set; } = default!;
 
     public bool? Active { get; set; }
 
-    public string ParentDropdownName { get; set; }
+    public string? ParentDropdownName { get; set; }
 
     public AbpTabTagHelper(AbpTabTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabTagHelperService.cs
index cac1cf231d..227bc0fd71 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabTagHelperService.cs
@@ -21,7 +21,7 @@ public class AbpTabTagHelperService : AbpTagHelperService<AbpTabTagHelper>
 
         var active = TagHelper.Active ?? false;
 
-        tabHeaderItems.Add(new TabItem(tabHeader, tabContent, active, TagHelper.Name, TagHelper.ParentDropdownName, false));
+        tabHeaderItems.Add(new TabItem(tabHeader, tabContent, active, TagHelper.Name!, TagHelper.ParentDropdownName, false));
 
         output.SuppressOutput();
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabsTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabsTagHelper.cs
index dced93a11c..141ca82d83 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabsTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/AbpTabsTagHelper.cs
@@ -5,7 +5,7 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Tab;
 
 public class AbpTabsTagHelper : AbpTagHelper<AbpTabsTagHelper, AbpTabsTagHelperService>
 {
-    public string Name { get; set; }
+    public string? Name { get; set; }
 
     public TabStyle TabStyle { get; set; } = TabStyle.Tab;
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/TabItem.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/TabItem.cs
index 5f10a4b89d..f1e7b13767 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/TabItem.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tab/TabItem.cs
@@ -2,7 +2,7 @@
 
 public class TabItem
 {
-    public TabItem(string header, string content, bool active, string id, string parentId, bool isDropdown)
+    public TabItem(string header, string content, bool active, string id, string? parentId, bool isDropdown)
     {
         Header = header;
         Content = content;
@@ -22,5 +22,5 @@ public class TabItem
 
     public string Id { get; set; }
 
-    public string ParentId { get; set; }
+    public string? ParentId { get; set; }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tooltip/AbpTooltipTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tooltip/AbpTooltipTagHelper.cs
index b1fda858d3..6cdc0ba9f9 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tooltip/AbpTooltipTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tooltip/AbpTooltipTagHelper.cs
@@ -14,17 +14,17 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Tooltip;
 [HtmlTargetElement("abp-button", Attributes = "abp-tooltip-bottom")]
 public class AbpTooltipTagHelper : AbpTagHelper<AbpTooltipTagHelper, AbpTooltipTagHelperService>
 {
-    public string AbpTooltip { get; set; }
+    public string? AbpTooltip { get; set; }
 
-    public string AbpTooltipRight { get; set; }
+    public string? AbpTooltipRight { get; set; }
 
-    public string AbpTooltipLeft { get; set; }
+    public string? AbpTooltipLeft { get; set; }
 
-    public string AbpTooltipTop { get; set; }
+    public string? AbpTooltipTop { get; set; }
 
-    public string AbpTooltipBottom { get; set; }
+    public string? AbpTooltipBottom { get; set; }
 
-    public string Title { get; set; }
+    public string? Title { get; set; }
 
     public AbpTooltipTagHelper(AbpTooltipTagHelperService tagHelperService)
         : base(tagHelperService)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tooltip/AbpTooltipTagHelperService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tooltip/AbpTooltipTagHelperService.cs
index 429a58b54b..dc5ce59328 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tooltip/AbpTooltipTagHelperService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/TagHelpers/Tooltip/AbpTooltipTagHelperService.cs
@@ -59,15 +59,15 @@ public class AbpTooltipTagHelperService : AbpTagHelperService<AbpTooltipTagHelpe
         switch (GetDirectory())
         {
             case TooltipDirectory.Top:
-                return TagHelper.AbpTooltipTop;
+                return TagHelper.AbpTooltipTop!;
             case TooltipDirectory.Right:
-                return TagHelper.AbpTooltipRight;
+                return TagHelper.AbpTooltipRight!;
             case TooltipDirectory.Bottom:
-                return TagHelper.AbpTooltipBottom;
+                return TagHelper.AbpTooltipBottom!;
             case TooltipDirectory.Left:
-                return TagHelper.AbpTooltipLeft;
+                return TagHelper.AbpTooltipLeft!;
             default:
-                return TagHelper.AbpTooltip;
+                return TagHelper.AbpTooltip!;
         }
     }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.csproj
index 75b09d631b..1480dc0de1 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap/Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
     <AssemblyName>Volo.Abp.AspNetCore.Mvc.UI.Bootstrap</AssemblyName>
     <PackageId>Volo.Abp.AspNetCore.Mvc.UI.Bootstrap</PackageId>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions.csproj
index 97d5b8b2a3..466589a027 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions.csproj
@@ -5,6 +5,8 @@
 
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
+        <WarningsAsErrors>Nullable</WarningsAsErrors>
         <RootNamespace />
     </PropertyGroup>
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundleConfigurationCollection.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundleConfigurationCollection.cs
index b972ae0840..36e981e698 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundleConfigurationCollection.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundleConfigurationCollection.cs
@@ -27,7 +27,7 @@ public class BundleConfigurationCollection
     /// <returns>Returns this object for chained calls.</returns>
     public BundleConfigurationCollection Add(
         [NotNull] string bundleName,
-        [CanBeNull] Action<BundleConfiguration> configureAction = null)
+        Action<BundleConfiguration>? configureAction = null)
     {
         if (!TryAdd(bundleName, configureAction))
         {
@@ -52,7 +52,7 @@ public class BundleConfigurationCollection
     /// <returns>Returns true if added. Returns false if it's already added before.</returns>
     public bool TryAdd(
         [NotNull] string bundleName,
-        [CanBeNull] Action<BundleConfiguration> configureAction = null,
+        Action<BundleConfiguration>? configureAction = null,
         bool overrideIfExists = false)
     {
         Check.NotNull(bundleName, nameof(bundleName));
@@ -78,7 +78,7 @@ public class BundleConfigurationCollection
         return true;
     }
 
-    private BundleConfiguration CreateBundle(string bundleName, Action<BundleConfiguration> configureAction)
+    private BundleConfiguration CreateBundle(string bundleName, Action<BundleConfiguration>? configureAction)
     {
         var bundle = new BundleConfiguration(bundleName);
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundleContributorCollection.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundleContributorCollection.cs
index 32dd23a6ee..5f245c1827 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundleContributorCollection.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling.Abstractions/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundleContributorCollection.cs
@@ -54,7 +54,7 @@ public class BundleContributorCollection
         if (!includeDependencies)
         {
             _contributors.ReplaceOne(x => x.GetType() == sourceContributorType,
-                contributor => (IBundleContributor)Activator.CreateInstance(destContributorType));
+                contributor => (IBundleContributor)Activator.CreateInstance(destContributorType)!);
         }
         else
         {
@@ -131,7 +131,7 @@ public class BundleContributorCollection
 
         try
         {
-            _contributors.Add((IBundleContributor)Activator.CreateInstance(contributorType));
+            _contributors.Add((IBundleContributor)Activator.CreateInstance(contributorType)!);
         }
         catch (Exception ex)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo.Abp.AspNetCore.Mvc.UI.Bundling.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo.Abp.AspNetCore.Mvc.UI.Bundling.csproj
index 535a907335..6e5cf50d57 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo.Abp.AspNetCore.Mvc.UI.Bundling.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo.Abp.AspNetCore.Mvc.UI.Bundling.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
     <AssemblyName>Volo.Abp.AspNetCore.Mvc.UI.Bundling</AssemblyName>
     <PackageId>Volo.Abp.AspNetCore.Mvc.UI.Bundling</PackageId>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundlerBase.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundlerBase.cs
index 285f8ea691..4b0efe54ab 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundlerBase.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/BundlerBase.cs
@@ -146,7 +146,7 @@ public abstract class BundlerBase : IBundler, ITransientDependency
         return false;
     }
 
-    protected virtual IFileInfo GetMinFileInfoOrNull(string file)
+    protected virtual IFileInfo? GetMinFileInfoOrNull(string file)
     {
         foreach (var suffix in _minFileSuffixes)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/Styles/CssRelativePath.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/Styles/CssRelativePath.cs
index 93332bf575..c41f0ca4a4 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/Styles/CssRelativePath.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/Styles/CssRelativePath.cs
@@ -20,7 +20,7 @@ internal static class CssRelativePath
             return cssFileContents;
         }
 
-        var cssDirectoryPath = Path.GetDirectoryName(absoluteInputFilePath);
+        var cssDirectoryPath = Path.GetDirectoryName(absoluteInputFilePath)!;
 
         foreach (Match match in matches)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpBundleItemTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpBundleItemTagHelper.cs
index f069f20190..1240dbef11 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpBundleItemTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpBundleItemTagHelper.cs
@@ -10,12 +10,12 @@ public abstract class AbpBundleItemTagHelper<TTagHelper, TTagHelperService> : Ab
     /// <summary>
     /// A file path.
     /// </summary>
-    public string Src { get; set; }
+    public string? Src { get; set; }
 
     /// <summary>
     /// A bundle contributor type.
     /// </summary>
-    public Type Type { get; set; }
+    public Type? Type { get; set; }
 
     protected AbpBundleItemTagHelper(TTagHelperService service)
         : base(service)
@@ -26,7 +26,7 @@ public abstract class AbpBundleItemTagHelper<TTagHelper, TTagHelperService> : Ab
     {
         if (Type != null)
         {
-            return Type.FullName;
+            return Type.FullName!;
         }
 
         if (Src != null)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpBundleTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpBundleTagHelper.cs
index d5fce59e4a..ca557436e9 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpBundleTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpBundleTagHelper.cs
@@ -6,7 +6,7 @@ public abstract class AbpBundleTagHelper<TTagHelper, TService> : AbpTagHelper<TT
     where TTagHelper : AbpTagHelper<TTagHelper, TService>
     where TService : class, IAbpTagHelperService<TTagHelper>
 {
-    public string Name { get; set; }
+    public string? Name { get; set; }
 
     protected AbpBundleTagHelper(TService service)
         : base(service)
@@ -14,7 +14,7 @@ public abstract class AbpBundleTagHelper<TTagHelper, TService> : AbpTagHelper<TT
 
     }
 
-    public virtual string GetNameOrNull()
+    public virtual string? GetNameOrNull()
     {
         return Name;
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpTagHelperResourceService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpTagHelperResourceService.cs
index 04a8761534..a247022674 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpTagHelperResourceService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/AbpTagHelperResourceService.cs
@@ -39,7 +39,7 @@ public abstract class AbpTagHelperResourceService : ITransientDependency
         [NotNull] TagHelperContext context,
         [NotNull] TagHelperOutput output,
         [NotNull] List<BundleTagHelperItem> bundleItems,
-        [CanBeNull] string bundleName = null)
+        string? bundleName = null)
     {
         Check.NotNull(viewContext, nameof(viewContext));
         Check.NotNull(context, nameof(context));
@@ -55,9 +55,9 @@ public abstract class AbpTagHelperResourceService : ITransientDependency
             bundleName = GenerateBundleName(bundleItems);
         }
 
-        CreateBundle(bundleName, bundleItems);
+        CreateBundle(bundleName!, bundleItems);
 
-        var bundleFiles = await GetBundleFilesAsync(bundleName);
+        var bundleFiles = await GetBundleFilesAsync(bundleName!);
 
         output.Content.Clear();
 
@@ -68,7 +68,7 @@ public abstract class AbpTagHelperResourceService : ITransientDependency
             if (file == null || !file.Exists)
             {
                 Logger.LogError($"Could not find the bundle file '{bundleFile}' for the bundle '{bundleName}'!");
-                AddErrorScript(viewContext, tagHelper, context, output, bundleFile, bundleName);
+                AddErrorScript(viewContext, tagHelper, context, output, bundleFile, bundleName!);
                 continue;
             }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/BundleTagHelperContributorTypeItem.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/BundleTagHelperContributorTypeItem.cs
index 5fac826e8b..bab02a9f97 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/BundleTagHelperContributorTypeItem.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/BundleTagHelperContributorTypeItem.cs
@@ -6,7 +6,7 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Bundling.TagHelpers;
 public class BundleTagHelperContributorTypeItem : BundleTagHelperItem
 {
     [NotNull]
-    public Type Type { get; }
+    public Type Type { get; } = default!;
 
     public BundleTagHelperContributorTypeItem([NotNull] Type type)
     {
@@ -15,7 +15,7 @@ public class BundleTagHelperContributorTypeItem : BundleTagHelperItem
 
     public override string ToString()
     {
-        return Type.FullName;
+        return Type.FullName!;
     }
 
     public override void AddToConfiguration(BundleConfiguration configuration)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/IBundleTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/IBundleTagHelper.cs
index 233298c16c..74d936964e 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/IBundleTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/IBundleTagHelper.cs
@@ -2,5 +2,5 @@
 
 public interface IBundleTagHelper
 {
-    string GetNameOrNull();
+    string? GetNameOrNull();
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/ScriptNonceTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/ScriptNonceTagHelper.cs
index 6c29c81073..08f99e3c0b 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/ScriptNonceTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Bundling/Volo/Abp/AspNetCore/Mvc/UI/Bundling/TagHelpers/ScriptNonceTagHelper.cs
@@ -11,7 +11,7 @@ public class ScriptNonceTagHelper : AbpTagHelper
 {
     [HtmlAttributeNotBound]
     [ViewContext]
-    public ViewContext ViewContext { get; set; }
+    public ViewContext ViewContext { get; set; } = default!;
     public override void Process(TagHelperContext context, TagHelperOutput output)
     {
         if (ViewContext.HttpContext.Items.TryGetValue(AbpAspNetCoreConsts.ScriptNonceKey, out var nonce) && nonce is string nonceString && !string.IsNullOrEmpty(nonceString))
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy/Pages/Abp/MultiTenancy/TenantSwitchModal.cshtml.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy/Pages/Abp/MultiTenancy/TenantSwitchModal.cshtml.cs
index 0110aeff21..f6711be826 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy/Pages/Abp/MultiTenancy/TenantSwitchModal.cshtml.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy/Pages/Abp/MultiTenancy/TenantSwitchModal.cshtml.cs
@@ -15,7 +15,7 @@ namespace Pages.Abp.MultiTenancy;
 public class TenantSwitchModalModel : AbpPageModel
 {
     [BindProperty]
-    public TenantInfoModel Input { get; set; }
+    public TenantInfoModel Input { get; set; } = default!;
 
     protected ITenantStore TenantStore { get; }
     protected AbpAspNetCoreMultiTenancyOptions Options { get; }
@@ -45,15 +45,15 @@ public class TenantSwitchModalModel : AbpPageModel
         Guid? tenantId = null;
         if (!Input.Name.IsNullOrEmpty())
         {
-            var tenant = await TenantStore.FindAsync(Input.Name);
+            var tenant = await TenantStore.FindAsync(Input.Name!);
             if (tenant == null)
             {
-                throw new UserFriendlyException(L["GivenTenantIsNotExist", Input.Name]);
+                throw new UserFriendlyException(L["GivenTenantIsNotExist", Input.Name!]);
             }
 
             if (!tenant.IsActive)
             {
-                throw new UserFriendlyException(L["GivenTenantIsNotAvailable", Input.Name]);
+                throw new UserFriendlyException(L["GivenTenantIsNotAvailable", Input.Name!]);
             }
 
             tenantId = tenant.Id;
@@ -65,6 +65,6 @@ public class TenantSwitchModalModel : AbpPageModel
     public class TenantInfoModel
     {
         [InputInfoText("SwitchTenantHint")]
-        public string Name { get; set; }
+        public string? Name { get; set; }
     }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy.csproj
index ed68be0443..c2fad00e3c 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy/Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
     <AssemblyName>Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy</AssemblyName>
     <PackageId>Volo.Abp.AspNetCore.Mvc.UI.MultiTenancy</PackageId>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Packages/Volo.Abp.AspNetCore.Mvc.UI.Packages.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Packages/Volo.Abp.AspNetCore.Mvc.UI.Packages.csproj
index 26bcc85cf7..40bed2322c 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Packages/Volo.Abp.AspNetCore.Mvc.UI.Packages.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Packages/Volo.Abp.AspNetCore.Mvc.UI.Packages.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
     <AssemblyName>Volo.Abp.AspNetCore.Mvc.UI.Packages</AssemblyName>
     <PackageId>Volo.Abp.AspNetCore.Mvc.UI.Packages</PackageId>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/DropdownsDemo/DropDownDemoDemoModel.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/DropdownsDemo/DropDownDemoDemoModel.cs
index 2ef2cb39ae..3399b88a70 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/DropdownsDemo/DropDownDemoDemoModel.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/DropdownsDemo/DropDownDemoDemoModel.cs
@@ -6,11 +6,11 @@ public class DropDownDemoDemoModel
 {
     [Required]
     [EmailAddress]
-    public string EmailAddress { get; set; }
+    public string EmailAddress { get; set; } = default!;
 
     [Required]
     [DataType(DataType.Password)]
-    public string Password { get; set; }
+    public string Password { get; set; } = default!;
 
     public bool RememberMe { get; set; }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/DynamicFormsDemo/DynamicFormsDemoModel.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/DynamicFormsDemo/DynamicFormsDemoModel.cs
index bebf364ba9..48853c9552 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/DynamicFormsDemo/DynamicFormsDemoModel.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/DynamicFormsDemo/DynamicFormsDemoModel.cs
@@ -40,7 +40,7 @@ public class DynamicFormsDemoModel
         [Required]
         [DataType(DataType.Password)]
         [Display(Name = "Password")]
-        public string Password { get; set; }
+        public string Password { get; set; } = default!;
 
         [Display(Name = "Is Active")]
         public bool IsActive { get; set; }
@@ -87,34 +87,34 @@ public class DynamicFormsDemoModel
     public class OrderExampleModel
     {
         [DisplayOrder(10005)]
-        public string Surname { get; set; }
+        public string? Surname { get; set; }
 
         //Default 10000
-        public string EmailAddress { get; set; }
+        public string? EmailAddress { get; set; }
 
         [DisplayOrder(10003)]
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         [DisplayOrder(9999)]
-        public string City { get; set; }
+        public string? City { get; set; }
     }
 
     public class AttributeExamplesModel
     {
         [HiddenInput]
-        public string HiddenInput { get; set; }
+        public string? HiddenInput { get; set; }
 
         [DisabledInput]
-        public string DisabledInput { get; set; }
+        public string? DisabledInput { get; set; }
 
         [ReadOnlyInput]
-        public string ReadonlyInput { get; set; }
+        public string? ReadonlyInput { get; set; }
 
         [FormControlSize(AbpFormControlSize.Large)]
-        public string LargeInput { get; set; }
+        public string? LargeInput { get; set; }
 
         [FormControlSize(AbpFormControlSize.Small)]
-        public string SmallInput { get; set; }
+        public string? SmallInput { get; set; }
     }
 
     public DetailedModel MyDetailedModel { get; set; }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/FormElementsDemo/FormElementsDemoModel.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/FormElementsDemo/FormElementsDemoModel.cs
index 5dc339ef6c..f9c5326471 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/FormElementsDemo/FormElementsDemoModel.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/FormElementsDemo/FormElementsDemoModel.cs
@@ -26,11 +26,11 @@ public class FormElementsDemoModel
     public class InformMeModel
     {
         [Required]
-        public string Name { get; set; }
+        public string Name { get; set; } = default!;
 
         [Required]
         [DataType(DataType.Password)]
-        public string Password { get; set; }
+        public string Password { get; set; } = default!;
 
         public bool CheckMeOut { get; set; }
     }
@@ -38,14 +38,14 @@ public class FormElementsDemoModel
     public class DetailsModel
     {
         [Required]
-        public string EmailAddress { get; set; }
+        public string EmailAddress { get; set; } = default!;
 
-        public string City { get; set; }
+        public string? City { get; set; }
 
-        public List<string> Cities { get; set; }
+        public List<string>? Cities { get; set; }
 
         [TextArea]
-        public string Description { get; set; }
+        public string? Description { get; set; }
     }
 
     public class CheckboxModel
@@ -58,7 +58,7 @@ public class FormElementsDemoModel
     public class CityRadioModel
     {
         [Display(Name = "City")]
-        public string CityRadio { get; set; }
+        public string? CityRadio { get; set; }
     }
 
     public class EnumModel
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/PaginatorDemo/PaginatorDemoViewComponent.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/PaginatorDemo/PaginatorDemoViewComponent.cs
index e5a02582a1..c19fdf54fb 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/PaginatorDemo/PaginatorDemoViewComponent.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/Demos/PaginatorDemo/PaginatorDemoViewComponent.cs
@@ -13,7 +13,7 @@ public class PaginatorDemoViewComponent : AbpViewComponent
 {
     public const string ViewPath = "/Views/Components/Themes/Shared/Demos/PaginatorDemo/Default.cshtml";
 
-    public PagerModel PagerModel { get; set; }
+    public PagerModel PagerModel { get; set; } = default!;
 
     public IViewComponentResult Invoke(PagerModel pagerModel)
     {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/TagHelpers/AbpComponentDemoSectionTagHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/TagHelpers/AbpComponentDemoSectionTagHelper.cs
index e3b6a15b46..29359bfabc 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/TagHelpers/AbpComponentDemoSectionTagHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Views/Components/Themes/Shared/TagHelpers/AbpComponentDemoSectionTagHelper.cs
@@ -14,8 +14,8 @@ public class AbpComponentDemoSectionTagHelper : AbpTagHelper
     private const string DemoSectionOpeningTag = "<abp-component-demo-section";
     private const string DemoSectionClosingTag = "</abp-component-demo-section";
 
-    public string ViewPath { get; set; }
-    public string Title { get; set; }
+    public string ViewPath { get; set; } = default!;
+    public string? Title { get; set; }
 
     private readonly IVirtualFileProvider _virtualFileProvider;
     private readonly IGuidGenerator _guidGenerator;
@@ -101,7 +101,7 @@ public class AbpComponentDemoSectionTagHelper : AbpTagHelper
 
     private string GetRawDemoSource()
     {
-        StringBuilder sourceBuilder = null;
+        StringBuilder? sourceBuilder = null;
 
         var lines = GetFileContent().SplitToLines();
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo.csproj
index c576f7897d..56da56c227 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
     <AssemblyName>Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo</AssemblyName>
     <PackageId>Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Demo</PackageId>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/AbpPageToolbarOptions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/AbpPageToolbarOptions.cs
index 52dcfd6085..0f4d21c6ac 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/AbpPageToolbarOptions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/AbpPageToolbarOptions.cs
@@ -16,7 +16,7 @@ public class AbpPageToolbarOptions
     public void Configure<TPage>([NotNull] Action<PageToolbar> configureAction)
     {
         // ReSharper disable once AssignNullToNotNullAttribute
-        Configure(typeof(TPage).FullName, configureAction);
+        Configure(typeof(TPage).FullName!, configureAction);
     }
 
     public void Configure([NotNull] string pageName, [NotNull] Action<PageToolbar> configureAction)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/PageToolbarExtensions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/PageToolbarExtensions.cs
index be64f07bc1..e319354d67 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/PageToolbarExtensions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/PageToolbarExtensions.cs
@@ -11,9 +11,9 @@ public static class PageToolbarExtensions
 {
     public static PageToolbar AddComponent<TComponent>(
         this PageToolbar toolbar,
-        object argument = null,
+        object? argument = null,
         int order = 0,
-        string requiredPolicyName = null)
+        string? requiredPolicyName = null)
     {
         return toolbar.AddComponent(
             typeof(TComponent),
@@ -26,9 +26,9 @@ public static class PageToolbarExtensions
     public static PageToolbar AddComponent(
         this PageToolbar toolbar,
         Type componentType,
-        object argument = null,
+        object? argument = null,
         int order = 0,
-        string requiredPolicyName = null)
+        string? requiredPolicyName = null)
     {
         toolbar.Contributors.Add(
             new SimplePageToolbarContributor(
@@ -45,16 +45,16 @@ public static class PageToolbarExtensions
     public static PageToolbar AddButton(
         this PageToolbar toolbar,
         ILocalizableString text,
-        string icon = null,
-        string name = null,
-        string id = null,
-        ILocalizableString busyText = null,
+        string? icon = null,
+        string? name = null,
+        string? id = null,
+        ILocalizableString? busyText = null,
         FontIconType iconType = FontIconType.FontAwesome,
         AbpButtonType type = AbpButtonType.Primary,
         AbpButtonSize size = AbpButtonSize.Small,
         bool disabled = false,
         int order = 0,
-        string requiredPolicyName = null)
+        string? requiredPolicyName = null)
     {
         if (busyText == null)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/PageToolbarItem.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/PageToolbarItem.cs
index e9cebae8f6..30cfa05664 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/PageToolbarItem.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/PageToolbarItem.cs
@@ -8,14 +8,13 @@ public class PageToolbarItem
     [NotNull]
     public Type ComponentType { get; }
 
-    [CanBeNull]
-    public object Arguments { get; set; }
+    public object? Arguments { get; set; }
 
     public int Order { get; set; }
 
     public PageToolbarItem(
         [NotNull] Type componentType,
-        [CanBeNull] object arguments = null,
+        object? arguments = null,
         int order = 0)
     {
         ComponentType = Check.NotNull(componentType, nameof(componentType));
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/SimplePageToolbarContributor.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/SimplePageToolbarContributor.cs
index 713c3c52ca..f049ef2c74 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/SimplePageToolbarContributor.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/PageToolbars/SimplePageToolbarContributor.cs
@@ -9,17 +9,17 @@ public class SimplePageToolbarContributor : IPageToolbarContributor
 {
     public Type ComponentType { get; }
 
-    public object Argument { get; set; }
+    public object? Argument { get; set; }
 
     public int Order { get; }
 
-    public string RequiredPolicyName { get; }
+    public string? RequiredPolicyName { get; }
 
     public SimplePageToolbarContributor(
         Type componentType,
-        object argument = null,
+        object? argument = null,
         int order = 0,
-        string requiredPolicyName = null)
+        string? requiredPolicyName = null)
     {
         ComponentType = componentType;
         Argument = argument;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Pages/Shared/Components/AbpApplicationPath/AbpApplicationPathViewComponentModel.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Pages/Shared/Components/AbpApplicationPath/AbpApplicationPathViewComponentModel.cs
index 94e8171102..7be33d9761 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Pages/Shared/Components/AbpApplicationPath/AbpApplicationPathViewComponentModel.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Pages/Shared/Components/AbpApplicationPath/AbpApplicationPathViewComponentModel.cs
@@ -2,5 +2,5 @@
 
 public class AbpApplicationPathViewComponentModel
 {
-    public string ApplicationPath { get; set; }
+    public string ApplicationPath { get; set; } = default!;
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Pages/Shared/Components/AbpPageToolbar/Button/AbpPageToolbarButtonViewComponent.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Pages/Shared/Components/AbpPageToolbar/Button/AbpPageToolbarButtonViewComponent.cs
index 56ae47f0c8..a403155668 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Pages/Shared/Components/AbpPageToolbar/Button/AbpPageToolbarButtonViewComponent.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Pages/Shared/Components/AbpPageToolbar/Button/AbpPageToolbarButtonViewComponent.cs
@@ -21,7 +21,7 @@ public class AbpPageToolbarButtonViewComponent : AbpViewComponent
         string name,
         string icon,
         string id,
-        ILocalizableString busyText,
+        ILocalizableString? busyText,
         FontIconType iconType,
         AbpButtonType type,
         AbpButtonSize size,
@@ -36,7 +36,7 @@ public class AbpPageToolbarButtonViewComponent : AbpViewComponent
                 name,
                 icon,
                 id,
-                busyText == null ? null : await busyText.LocalizeAsync(StringLocalizerFactory),
+                busyText == null ? null : (await busyText.LocalizeAsync(StringLocalizerFactory)).ToString(),
                 iconType,
                 type,
                 size,
@@ -51,7 +51,7 @@ public class AbpPageToolbarButtonViewComponent : AbpViewComponent
         public string Name { get; }
         public string Icon { get; }
         public string Id { get; }
-        public string BusyText { get; }
+        public string? BusyText { get; }
         public FontIconType IconType { get; }
         public AbpButtonType Type { get; }
         public AbpButtonSize Size { get; }
@@ -62,7 +62,7 @@ public class AbpPageToolbarButtonViewComponent : AbpViewComponent
             string name,
             string icon,
             string id,
-            string busyText,
+            string? busyText,
             FontIconType iconType,
             AbpButtonType type,
             AbpButtonSize size,
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/IToolbarConfigurationContext.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/IToolbarConfigurationContext.cs
index bb1365112c..740ca05979 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/IToolbarConfigurationContext.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/IToolbarConfigurationContext.cs
@@ -20,8 +20,7 @@ public interface IToolbarConfigurationContext : IServiceProviderAccessor
 
     Task<bool> IsGrantedAsync(string policyName);
 
-    [CanBeNull]
-    IStringLocalizer GetDefaultLocalizer();
+    IStringLocalizer? GetDefaultLocalizer();
 
     [NotNull]
     public IStringLocalizer GetLocalizer<T>();
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/ToolbarConfigurationContext.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/ToolbarConfigurationContext.cs
index b1f1ccadf4..fa67fba2b9 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/ToolbarConfigurationContext.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/ToolbarConfigurationContext.cs
@@ -36,8 +36,7 @@ public class ToolbarConfigurationContext : IToolbarConfigurationContext
         return AuthorizationService.IsGrantedAsync(policyName);
     }
 
-    [CanBeNull]
-    public IStringLocalizer GetDefaultLocalizer()
+    public IStringLocalizer? GetDefaultLocalizer()
     {
         return StringLocalizerFactory.CreateDefaultOrNull();
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/ToolbarItem.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/ToolbarItem.cs
index 89d904c13b..0bf354bde6 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/ToolbarItem.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Toolbars/ToolbarItem.cs
@@ -11,17 +11,16 @@ public class ToolbarItem : IHasSimpleStateCheckers<ToolbarItem>
         get => _componentType;
         set => _componentType = Check.NotNull(value, nameof(value));
     }
-    private Type _componentType;
+    private Type _componentType = default!;
 
     public int Order { get; set; }
 
-    [CanBeNull]
     [Obsolete("Use RequirePermissions extension method.")]
-    public string RequiredPermissionName { get; set; }
+    public string? RequiredPermissionName { get; set; }
 
     public List<ISimpleStateChecker<ToolbarItem>> StateCheckers { get; }
 
-    public ToolbarItem([NotNull] Type componentType, int order = 0, string requiredPermissionName = null)
+    public ToolbarItem([NotNull] Type componentType, int order = 0, string? requiredPermissionName = null)
     {
         Order = order;
         ComponentType = Check.NotNull(componentType, nameof(componentType));
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Views/Error/AbpErrorViewModel.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Views/Error/AbpErrorViewModel.cs
index 3863604a09..c68b6b3094 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Views/Error/AbpErrorViewModel.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Views/Error/AbpErrorViewModel.cs
@@ -4,7 +4,7 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.Views.Error;
 
 public class AbpErrorViewModel
 {
-    public RemoteServiceErrorInfo ErrorInfo { get; set; }
+    public RemoteServiceErrorInfo ErrorInfo { get; set; } = default!;
 
     public int HttpStatusCode { get; set; }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Views/Error/Default.cshtml b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Views/Error/Default.cshtml
index cfd16a2b8c..f02e487cb2 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Views/Error/Default.cshtml
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Views/Error/Default.cshtml
@@ -26,7 +26,7 @@
         <p>
             @if (!Model.ErrorInfo.ValidationErrors.IsNullOrEmpty())
             {
-                foreach (var validationError in Model.ErrorInfo.ValidationErrors)
+                foreach (var validationError in Model.ErrorInfo.ValidationErrors!)
                 {
                     <text>* </text>@(validationError.Message)
                     if (validationError.Members != null && validationError.Members.Any())
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.csproj
index 40f95d10c9..4bac31ac83 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared/Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
     <AssemblyName>Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared</AssemblyName>
     <PackageId>Volo.Abp.AspNetCore.Mvc.UI.Theme.Shared</PackageId>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo.Abp.AspNetCore.Mvc.UI.Widgets.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo.Abp.AspNetCore.Mvc.UI.Widgets.csproj
index cbb3d106a1..25106fee56 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo.Abp.AspNetCore.Mvc.UI.Widgets.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo.Abp.AspNetCore.Mvc.UI.Widgets.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
     <AssemblyName>Volo.Abp.AspNetCore.Mvc.UI.Widgets</AssemblyName>
     <PackageId>Volo.Abp.AspNetCore.Mvc.UI.Widgets</PackageId>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/AbpViewComponentHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/AbpViewComponentHelper.cs
index 764169fd06..c55ea9dd4c 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/AbpViewComponentHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/AbpViewComponentHelper.cs
@@ -28,7 +28,7 @@ public class AbpViewComponentHelper : IViewComponentHelper, IViewContextAware, I
         Options = widgetOptions.Value;
     }
 
-    public virtual async Task<IHtmlContent> InvokeAsync(string name, object arguments)
+    public virtual async Task<IHtmlContent> InvokeAsync(string name, object? arguments)
     {
         var widget = Options.Widgets.Find(name);
         if (widget == null)
@@ -39,7 +39,7 @@ public class AbpViewComponentHelper : IViewComponentHelper, IViewContextAware, I
         return await InvokeWidgetAsync(arguments, widget);
     }
 
-    public virtual async Task<IHtmlContent> InvokeAsync(Type componentType, object arguments)
+    public virtual async Task<IHtmlContent> InvokeAsync(Type componentType, object? arguments)
     {
         var widget = Options.Widgets.Find(componentType);
         if (widget == null)
@@ -55,7 +55,7 @@ public class AbpViewComponentHelper : IViewComponentHelper, IViewContextAware, I
         DefaultViewComponentHelper.Contextualize(viewContext);
     }
 
-    protected virtual async Task<IHtmlContent> InvokeWidgetAsync(object arguments, WidgetDefinition widget)
+    protected virtual async Task<IHtmlContent> InvokeWidgetAsync(object? arguments, WidgetDefinition widget)
     {
         PageWidgetManager.TryAdd(widget);
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/Components/WidgetResourcesViewModel.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/Components/WidgetResourcesViewModel.cs
index 8430ba6b91..11dff8def7 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/Components/WidgetResourcesViewModel.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/Components/WidgetResourcesViewModel.cs
@@ -4,5 +4,6 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Widgets.Components;
 
 public class WidgetResourcesViewModel
 {
-    public IReadOnlyList<WidgetDefinition> Widgets { get; set; }
+    public IReadOnlyList<WidgetDefinition> Widgets { get; set; } = default!;
+
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetAttribute.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetAttribute.cs
index 2cc1b9232d..31fc18a8a0 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetAttribute.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetAttribute.cs
@@ -8,30 +8,23 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Widgets;
 [AttributeUsage(AttributeTargets.Class)]
 public class WidgetAttribute : Attribute
 {
-    [CanBeNull]
-    public string[] StyleFiles { get; set; }
+    public string[]? StyleFiles { get; set; }
 
-    [CanBeNull]
-    public Type[] StyleTypes { get; set; }
+    public Type[]? StyleTypes { get; set; }
 
-    [CanBeNull]
-    public string[] ScriptFiles { get; set; }
+    public string[]? ScriptFiles { get; set; }
 
-    [CanBeNull]
-    public Type[] ScriptTypes { get; set; }
+    public Type[]? ScriptTypes { get; set; }
 
-    [CanBeNull]
-    public string DisplayName { get; set; }
+    public string? DisplayName { get; set; }
 
-    [CanBeNull]
-    public Type DisplayNameResource { get; set; }
+    public Type? DisplayNameResource { get; set; }
 
-    [CanBeNull]
-    public string[] RequiredPolicies { get; set; }
+    public string[]? RequiredPolicies { get; set; }
 
     public bool RequiresAuthentication { get; set; }
 
-    public string RefreshUrl { get; set; }
+    public string? RefreshUrl { get; set; }
 
     public bool AutoInitialize { get; set; }
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetDefinition.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetDefinition.cs
index 2a9b213494..0e5d8b8edf 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetDefinition.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetDefinition.cs
@@ -26,7 +26,7 @@ public class WidgetDefinition
         get => _displayName;
         set => _displayName = Check.NotNull(value, nameof(value));
     }
-    private ILocalizableString _displayName;
+    private ILocalizableString _displayName = default!;
 
     [NotNull]
     public Type ViewComponentType { get; }
@@ -46,14 +46,13 @@ public class WidgetDefinition
     [NotNull]
     public List<WidgetResourceItem> Scripts { get; }
 
-    [CanBeNull]
-    public string RefreshUrl { get; set; }
+    public string? RefreshUrl { get; set; }
 
     public bool AutoInitialize { get; set; }
 
     public WidgetDefinition(
         [NotNull] Type viewComponentType,
-        [CanBeNull] ILocalizableString displayName = null)
+        ILocalizableString? displayName = null)
     {
         ViewComponentType = Check.NotNull(viewComponentType, nameof(viewComponentType));
 
@@ -74,12 +73,12 @@ public class WidgetDefinition
 
         if (!widgetAttribute.StyleTypes.IsNullOrEmpty())
         {
-            styles.AddRange(widgetAttribute.StyleTypes.Select(type => new WidgetResourceItem(type)));
+            styles.AddRange(widgetAttribute.StyleTypes!.Select(type => new WidgetResourceItem(type)));
         }
 
         if (!widgetAttribute.StyleFiles.IsNullOrEmpty())
         {
-            styles.AddRange(widgetAttribute.StyleFiles.Select(src => new WidgetResourceItem(src)));
+            styles.AddRange(widgetAttribute.StyleFiles!.Select(src => new WidgetResourceItem(src)));
         }
 
         return styles;
@@ -91,12 +90,12 @@ public class WidgetDefinition
 
         if (!widgetAttribute.ScriptTypes.IsNullOrEmpty())
         {
-            scripts.AddRange(widgetAttribute.ScriptTypes.Select(type => new WidgetResourceItem(type)));
+            scripts.AddRange(widgetAttribute.ScriptTypes!.Select(type => new WidgetResourceItem(type)));
         }
 
         if (!widgetAttribute.ScriptFiles.IsNullOrEmpty())
         {
-            scripts.AddRange(widgetAttribute.ScriptFiles.Select(src => new WidgetResourceItem(src)));
+            scripts.AddRange(widgetAttribute.ScriptFiles!.Select(src => new WidgetResourceItem(src)));
         }
 
         return scripts;
@@ -108,7 +107,7 @@ public class WidgetDefinition
 
         if (!widgetAttribute.RequiredPolicies.IsNullOrEmpty())
         {
-            policies.AddRange(widgetAttribute.RequiredPolicies);
+            policies.AddRange(widgetAttribute.RequiredPolicies!);
         }
 
         return policies;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetDefinitionCollection.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetDefinitionCollection.cs
index db4266b872..b0e56f3826 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetDefinitionCollection.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetDefinitionCollection.cs
@@ -30,34 +30,31 @@ public class WidgetDefinitionCollection
     }
 
     public WidgetDefinition Add<TViewComponent>(
-        [CanBeNull] ILocalizableString displayName = null)
+        ILocalizableString? displayName = null)
     {
         return Add(typeof(TViewComponent), displayName);
     }
 
     public WidgetDefinition Add(
         [NotNull] Type viewComponentType,
-        [CanBeNull] ILocalizableString displayName = null)
+        ILocalizableString? displayName = null)
     {
         var widget = new WidgetDefinition(viewComponentType, displayName);
         Add(widget);
         return widget;
     }
 
-    [CanBeNull]
-    public WidgetDefinition Find(string name)
+    public WidgetDefinition? Find(string name)
     {
         return _widgetsByName.GetOrDefault(name);
     }
 
-    [CanBeNull]
-    public WidgetDefinition Find<TViewComponent>()
+    public WidgetDefinition? Find<TViewComponent>()
     {
         return Find(typeof(TViewComponent));
     }
 
-    [CanBeNull]
-    public WidgetDefinition Find(Type viewComponentType)
+    public WidgetDefinition? Find(Type viewComponentType)
     {
         return _widgetsByType.GetOrDefault(viewComponentType);
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetManager.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetManager.cs
index f86a457058..422f628a9e 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetManager.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetManager.cs
@@ -27,7 +27,7 @@ public class WidgetManager : IWidgetManager
     {
         var widget = Options.Widgets.Find(widgetComponentType);
 
-        return await IsGrantedAsyncInternal(widget, widgetComponentType.FullName);
+        return await IsGrantedAsyncInternal(widget, widgetComponentType.FullName!);
     }
 
     public async Task<bool> IsGrantedAsync(string name)
@@ -37,7 +37,7 @@ public class WidgetManager : IWidgetManager
         return await IsGrantedAsyncInternal(widget, name);
     }
 
-    private async Task<bool> IsGrantedAsyncInternal(WidgetDefinition widget, string wantedWidgetName)
+    private async Task<bool> IsGrantedAsyncInternal(WidgetDefinition? widget, string wantedWidgetName)
     {
         if (widget == null)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetResourceItem.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetResourceItem.cs
index 29cff2faef..1b2f800649 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetResourceItem.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI.Widgets/Volo/Abp/AspNetCore/Mvc/UI/Widgets/WidgetResourceItem.cs
@@ -5,11 +5,9 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Widgets;
 
 public class WidgetResourceItem
 {
-    [CanBeNull]
-    public string Src { get; }
+    public string? Src { get; }
 
-    [CanBeNull]
-    public Type Type { get; }
+    public Type? Type { get; }
 
     public WidgetResourceItem([NotNull] string src)
     {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo.Abp.AspNetCore.Mvc.UI.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo.Abp.AspNetCore.Mvc.UI.csproj
index 1975ba8a67..1d1234a147 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo.Abp.AspNetCore.Mvc.UI.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo.Abp.AspNetCore.Mvc.UI.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
     <AssemblyName>Volo.Abp.AspNetCore.Mvc.UI</AssemblyName>
     <PackageId>Volo.Abp.AspNetCore.Mvc.UI</PackageId>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Alerts/AlertList.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Alerts/AlertList.cs
index 123cdfff33..279a1674a3 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Alerts/AlertList.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Alerts/AlertList.cs
@@ -4,27 +4,27 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Alerts;
 
 public class AlertList : List<AlertMessage>
 {
-    public void Add(AlertType type, string text, string title = null, bool dismissible = true)
+    public void Add(AlertType type, string text, string? title = null, bool dismissible = true)
     {
         Add(new AlertMessage(type, text, title, dismissible));
     }
 
-    public void Info(string text, string title = null, bool dismissible = true)
+    public void Info(string text, string? title = null, bool dismissible = true)
     {
         Add(new AlertMessage(AlertType.Info, text, title, dismissible));
     }
 
-    public void Warning(string text, string title = null, bool dismissible = true)
+    public void Warning(string text, string? title = null, bool dismissible = true)
     {
         Add(new AlertMessage(AlertType.Warning, text, title, dismissible));
     }
 
-    public void Danger(string text, string title = null, bool dismissible = true)
+    public void Danger(string text, string? title = null, bool dismissible = true)
     {
         Add(new AlertMessage(AlertType.Danger, text, title, dismissible));
     }
 
-    public void Success(string text, string title = null, bool dismissible = true)
+    public void Success(string text, string? title = null, bool dismissible = true)
     {
         Add(new AlertMessage(AlertType.Success, text, title, dismissible));
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Alerts/AlertMessage.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Alerts/AlertMessage.cs
index be725d20c1..42dbaf0086 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Alerts/AlertMessage.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Alerts/AlertMessage.cs
@@ -9,16 +9,16 @@ public class AlertMessage
         get => _text;
         set => _text = Check.NotNullOrWhiteSpace(value, nameof(value));
     }
-    private string _text;
+
+    private string _text = default!;
 
     public AlertType Type { get; set; }
 
-    [CanBeNull]
-    public string Title { get; set; }
+    public string? Title { get; set; }
 
     public bool Dismissible { get; set; }
 
-    public AlertMessage(AlertType type, [NotNull] string text, string title = null, bool dismissible = true)
+    public AlertMessage(AlertType type, [NotNull] string text, string? title = null, bool dismissible = true)
     {
         Type = type;
         Text = Check.NotNullOrWhiteSpace(text, nameof(text));
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/BreadCrumb.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/BreadCrumb.cs
index 7bc702662a..da210e7b78 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/BreadCrumb.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/BreadCrumb.cs
@@ -21,7 +21,7 @@ public class BreadCrumb
         Items = new List<BreadCrumbItem>();
     }
 
-    public void Add(string text, string url = null, string icon = null)
+    public void Add(string text, string? url = null, string? icon = null)
     {
         Items.Add(new BreadCrumbItem(text, url, icon));
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/BreadCrumbItem.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/BreadCrumbItem.cs
index 24b1208175..fd405f82ec 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/BreadCrumbItem.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/BreadCrumbItem.cs
@@ -4,11 +4,11 @@ public class BreadCrumbItem
 {
     public string Text { get; set; }
 
-    public string Icon { get; set; }
+    public string? Icon { get; set; }
 
-    public string Url { get; set; }
+    public string? Url { get; set; }
 
-    public BreadCrumbItem(string text, string url = null, string icon = null)
+    public BreadCrumbItem(string text, string? url = null, string? icon = null)
     {
         Text = text;
         Url = url;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/ContentLayout.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/ContentLayout.cs
index 188853f88d..1e5abce611 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/ContentLayout.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Layout/ContentLayout.cs
@@ -5,11 +5,11 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.Layout;
 
 public class ContentLayout
 {
-    public string Title { get; set; }
+    public string? Title { get; set; }
 
     public BreadCrumb BreadCrumb { get; }
 
-    public string MenuItemName { get; set; }
+    public string? MenuItemName { get; set; }
 
     public ContentLayout()
     {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/AbpPage.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/AbpPage.cs
index 4a1e6f505c..9028b82171 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/AbpPage.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/AbpPage.cs
@@ -7,5 +7,5 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.RazorPages;
 public abstract class AbpPage : Page
 {
     [RazorInject]
-    public ICurrentUser CurrentUser { get; set; }
+    public ICurrentUser CurrentUser { get; set; } = default!;
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/AbpPageModel.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/AbpPageModel.cs
index b2d3d1172b..907e462526 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/AbpPageModel.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/AbpPageModel.cs
@@ -25,10 +25,10 @@ namespace Volo.Abp.AspNetCore.Mvc.UI.RazorPages;
 
 public abstract class AbpPageModel : PageModel
 {
-    public IAbpLazyServiceProvider LazyServiceProvider { get; set; }
+    public IAbpLazyServiceProvider LazyServiceProvider { get; set; } = default!;
 
     [Obsolete("Use LazyServiceProvider instead.")]
-    public IServiceProvider ServiceProvider { get; set; }
+    public IServiceProvider ServiceProvider { get; set; } = default!;
 
     protected IClock Clock => LazyServiceProvider.LazyGetRequiredService<IClock>();
 
@@ -36,7 +36,7 @@ public abstract class AbpPageModel : PageModel
 
     protected IUnitOfWorkManager UnitOfWorkManager => LazyServiceProvider.LazyGetRequiredService<IUnitOfWorkManager>();
 
-    protected Type ObjectMapperContext { get; set; }
+    protected Type? ObjectMapperContext { get; set; }
     protected IObjectMapper ObjectMapper => LazyServiceProvider.LazyGetService<IObjectMapper>(provider =>
         ObjectMapperContext == null
             ? provider.GetRequiredService<IObjectMapper>()
@@ -59,9 +59,9 @@ public abstract class AbpPageModel : PageModel
         }
     }
 
-    private IStringLocalizer _localizer;
+    private IStringLocalizer? _localizer;
 
-    protected Type LocalizationResourceType { get; set; }
+    protected Type? LocalizationResourceType { get; set; }
 
     protected ICurrentUser CurrentUser => LazyServiceProvider.LazyGetRequiredService<ICurrentUser>();
 
@@ -75,9 +75,9 @@ public abstract class AbpPageModel : PageModel
 
     protected IAlertManager AlertManager => LazyServiceProvider.LazyGetRequiredService<IAlertManager>();
 
-    protected IUnitOfWork CurrentUnitOfWork => UnitOfWorkManager?.Current;
+    protected IUnitOfWork? CurrentUnitOfWork => UnitOfWorkManager?.Current;
 
-    protected ILogger Logger => LazyServiceProvider.LazyGetService<ILogger>(provider => LoggerFactory?.CreateLogger(GetType().FullName) ?? NullLogger.Instance);
+    protected ILogger Logger => LazyServiceProvider.LazyGetService<ILogger>(provider => LoggerFactory?.CreateLogger(GetType().FullName!) ?? NullLogger.Instance);
 
     protected IAppUrlProvider AppUrlProvider => LazyServiceProvider.LazyGetRequiredService<IAppUrlProvider>();
 
@@ -122,12 +122,12 @@ public abstract class AbpPageModel : PageModel
         return localizer;
     }
 
-    protected RedirectResult RedirectSafely(string returnUrl, string returnUrlHash = null)
+    protected RedirectResult RedirectSafely(string returnUrl, string? returnUrlHash = null)
     {
         return Redirect(GetRedirectUrl(returnUrl, returnUrlHash));
     }
 
-    protected virtual string GetRedirectUrl(string returnUrl, string returnUrlHash = null)
+    protected virtual string GetRedirectUrl(string returnUrl, string? returnUrlHash = null)
     {
         returnUrl = NormalizeReturnUrl(returnUrl);
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/ServiceBasedPageModelActivatorProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/ServiceBasedPageModelActivatorProvider.cs
index aa71f09ef8..c85d20373d 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/ServiceBasedPageModelActivatorProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/RazorPages/ServiceBasedPageModelActivatorProvider.cs
@@ -12,10 +12,10 @@ public class ServiceBasedPageModelActivatorProvider : IPageModelActivatorProvide
     public Func<PageContext, object> CreateActivator([NotNull] CompiledPageActionDescriptor descriptor)
     {
         Check.NotNull(descriptor, nameof(descriptor));
-        return context => context.HttpContext.RequestServices.GetRequiredService(descriptor.ModelTypeInfo);
+        return context => context.HttpContext.RequestServices.GetRequiredService(descriptor.ModelTypeInfo!);
     }
 
-    public Action<PageContext, object> CreateReleaser([NotNull] CompiledPageActionDescriptor descriptor)
+    public Action<PageContext, object>? CreateReleaser([NotNull] CompiledPageActionDescriptor descriptor)
     {
         return null;
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Theming/AbpThemingOptions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Theming/AbpThemingOptions.cs
index 6b45008e71..1197ad6e53 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Theming/AbpThemingOptions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Theming/AbpThemingOptions.cs
@@ -4,7 +4,7 @@ public class AbpThemingOptions
 {
     public ThemeDictionary Themes { get; }
 
-    public string DefaultThemeName { get; set; }
+    public string? DefaultThemeName { get; set; }
 
     public AbpThemingOptions()
     {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Theming/DefaultThemeManager.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Theming/DefaultThemeManager.cs
index 658923176f..39e97bc518 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Theming/DefaultThemeManager.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/AspNetCore/Mvc/UI/Theming/DefaultThemeManager.cs
@@ -27,7 +27,7 @@ public class DefaultThemeManager : IThemeManager, IScopedDependency, IServicePro
 
     protected virtual ITheme GetCurrentTheme()
     {
-        var preSelectedTheme = HttpContextAccessor.HttpContext.Items[CurrentThemeHttpContextKey] as ITheme;
+        var preSelectedTheme = HttpContextAccessor.HttpContext!.Items[CurrentThemeHttpContextKey] as ITheme;
 
         if (preSelectedTheme == null)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/ObjectExtending/MvcUiObjectExtensionPropertyInfoExtensions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/ObjectExtending/MvcUiObjectExtensionPropertyInfoExtensions.cs
index aa41bcd5a2..d4d1b796ee 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/ObjectExtending/MvcUiObjectExtensionPropertyInfoExtensions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc.UI/Volo/Abp/ObjectExtending/MvcUiObjectExtensionPropertyInfoExtensions.cs
@@ -35,7 +35,7 @@ public static class MvcUiObjectExtensionPropertyInfoExtensions
             typeof(decimal?)
         };
 
-    public static string GetInputFormatOrNull(this IBasicObjectExtensionPropertyInfo property)
+    public static string? GetInputFormatOrNull(this IBasicObjectExtensionPropertyInfo property)
     {
         var formatString = property.GetDataFormatStringOrNull();
 
@@ -57,7 +57,7 @@ public static class MvcUiObjectExtensionPropertyInfoExtensions
         return null;
     }
 
-    public static string GetInputValueOrNull(this IBasicObjectExtensionPropertyInfo property, object value)
+    public static string? GetInputValueOrNull(this IBasicObjectExtensionPropertyInfo property, object? value)
     {
         if (value == null)
         {
@@ -88,7 +88,7 @@ public static class MvcUiObjectExtensionPropertyInfoExtensions
                ?? "text"; //default
     }
 
-    private static string GetInputTypeFromAttributeOrNull(Attribute attribute)
+    private static string? GetInputTypeFromAttributeOrNull(Attribute attribute)
     {
         if (attribute is EmailAddressAttribute)
         {
@@ -134,7 +134,7 @@ public static class MvcUiObjectExtensionPropertyInfoExtensions
         return null;
     }
 
-    private static string GetInputTypeFromTypeOrNull(Type type)
+    private static string? GetInputTypeFromTypeOrNull(Type type)
     {
         if (type == typeof(bool))
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Microsoft/AspNetCore/Builder/AbpAspNetCoreMvcApplicationBuilderExtensions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Microsoft/AspNetCore/Builder/AbpAspNetCoreMvcApplicationBuilderExtensions.cs
index 3b9acc9f85..3409d0b19c 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Microsoft/AspNetCore/Builder/AbpAspNetCoreMvcApplicationBuilderExtensions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Microsoft/AspNetCore/Builder/AbpAspNetCoreMvcApplicationBuilderExtensions.cs
@@ -18,7 +18,7 @@ public static class AbpAspNetCoreMvcApplicationBuilderExtensions
     [Obsolete("Use app.UseConfiguredEndpoints(...) extension method instead!")]
     public static IApplicationBuilder UseMvcWithDefaultRouteAndArea(
         this IApplicationBuilder app,
-        Action<IEndpointRouteBuilder> additionalConfigurationAction = null)
+        Action<IEndpointRouteBuilder>? additionalConfigurationAction = null)
     {
         return app.UseConfiguredEndpoints(additionalConfigurationAction);
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Microsoft/AspNetCore/Mvc/Abstractions/ActionDescriptorExtensions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Microsoft/AspNetCore/Mvc/Abstractions/ActionDescriptorExtensions.cs
index 24c9b071bd..2d33f65b6d 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Microsoft/AspNetCore/Mvc/Abstractions/ActionDescriptorExtensions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Microsoft/AspNetCore/Mvc/Abstractions/ActionDescriptorExtensions.cs
@@ -16,7 +16,7 @@ public static class ActionDescriptorExtensions
             throw new AbpException($"{nameof(actionDescriptor)} should be type of {typeof(ControllerActionDescriptor).AssemblyQualifiedName}");
         }
 
-        return actionDescriptor as ControllerActionDescriptor;
+        return (actionDescriptor as ControllerActionDescriptor)!;
     }
 
     public static MethodInfo GetMethodInfo(this ActionDescriptor actionDescriptor)
@@ -51,6 +51,6 @@ public static class ActionDescriptorExtensions
             throw new AbpException($"{nameof(actionDescriptor)} should be type of {typeof(PageActionDescriptor).AssemblyQualifiedName}");
         }
 
-        return actionDescriptor as PageActionDescriptor;
+        return (actionDescriptor as PageActionDescriptor)!;
     }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo.Abp.AspNetCore.Mvc.csproj b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo.Abp.AspNetCore.Mvc.csproj
index 37b9822966..69cc963ca2 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo.Abp.AspNetCore.Mvc.csproj
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo.Abp.AspNetCore.Mvc.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
     <AssemblyName>Volo.Abp.AspNetCore.Mvc</AssemblyName>
     <PackageId>Volo.Abp.AspNetCore.Mvc</PackageId>
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpActionContextExtensions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpActionContextExtensions.cs
index 8c18edaf3e..ea63591826 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpActionContextExtensions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpActionContextExtensions.cs
@@ -11,7 +11,7 @@ public static class AbpActionContextExtensions
         return context.HttpContext.RequestServices.GetRequiredService<T>();
     }
 
-    public static T GetService<T>(this FilterContext context, T defaultValue = default)
+    public static T? GetService<T>(this FilterContext context, T? defaultValue = default)
         where T : class
     {
         return context.HttpContext.RequestServices.GetService<T>() ?? defaultValue;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpController.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpController.cs
index 51c0849c66..0a3f042784 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpController.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpController.cs
@@ -23,14 +23,14 @@ namespace Volo.Abp.AspNetCore.Mvc;
 
 public abstract class AbpController : Controller, IAvoidDuplicateCrossCuttingConcerns
 {
-    public IAbpLazyServiceProvider LazyServiceProvider { get; set; }
+    public IAbpLazyServiceProvider LazyServiceProvider { get; set; } = default!;
 
     [Obsolete("Use LazyServiceProvider instead.")]
-    public IServiceProvider ServiceProvider { get; set; }
+    public IServiceProvider ServiceProvider { get; set; } = default!;
 
     protected IUnitOfWorkManager UnitOfWorkManager => LazyServiceProvider.LazyGetRequiredService<IUnitOfWorkManager>();
 
-    protected Type ObjectMapperContext { get; set; }
+    protected Type? ObjectMapperContext { get; set; }
     protected IObjectMapper ObjectMapper => LazyServiceProvider.LazyGetService<IObjectMapper>(provider =>
         ObjectMapperContext == null
             ? provider.GetRequiredService<IObjectMapper>()
@@ -40,7 +40,7 @@ public abstract class AbpController : Controller, IAvoidDuplicateCrossCuttingCon
 
     protected ILoggerFactory LoggerFactory => LazyServiceProvider.LazyGetRequiredService<ILoggerFactory>();
 
-    protected ILogger Logger => LazyServiceProvider.LazyGetService<ILogger>(provider => LoggerFactory?.CreateLogger(GetType().FullName) ?? NullLogger.Instance);
+    protected ILogger Logger => LazyServiceProvider.LazyGetService<ILogger>(provider => LoggerFactory?.CreateLogger(GetType().FullName!) ?? NullLogger.Instance);
 
     protected ICurrentUser CurrentUser => LazyServiceProvider.LazyGetRequiredService<ICurrentUser>();
 
@@ -48,7 +48,7 @@ public abstract class AbpController : Controller, IAvoidDuplicateCrossCuttingCon
 
     protected IAuthorizationService AuthorizationService => LazyServiceProvider.LazyGetRequiredService<IAuthorizationService>();
 
-    protected IUnitOfWork CurrentUnitOfWork => UnitOfWorkManager?.Current;
+    protected IUnitOfWork? CurrentUnitOfWork => UnitOfWorkManager?.Current;
 
     protected IClock Clock => LazyServiceProvider.LazyGetRequiredService<IClock>();
 
@@ -70,16 +70,16 @@ public abstract class AbpController : Controller, IAvoidDuplicateCrossCuttingCon
             return _localizer;
         }
     }
-    private IStringLocalizer _localizer;
+    private IStringLocalizer? _localizer;
 
-    protected Type LocalizationResource {
+    protected Type? LocalizationResource {
         get => _localizationResource;
         set {
             _localizationResource = value;
             _localizer = null;
         }
     }
-    private Type _localizationResource = typeof(DefaultResource);
+    private Type? _localizationResource = typeof(DefaultResource);
 
     public List<string> AppliedCrossCuttingConcerns { get; } = new List<string>();
 
@@ -104,12 +104,12 @@ public abstract class AbpController : Controller, IAvoidDuplicateCrossCuttingCon
         return localizer;
     }
 
-    protected virtual RedirectResult RedirectSafely(string returnUrl, string returnUrlHash = null)
+    protected virtual RedirectResult RedirectSafely(string returnUrl, string? returnUrlHash = null)
     {
         return Redirect(GetRedirectUrl(returnUrl, returnUrlHash));
     }
 
-    protected virtual string GetRedirectUrl(string returnUrl, string returnUrlHash = null)
+    protected virtual string GetRedirectUrl(string returnUrl, string? returnUrlHash = null)
     {
         returnUrl = NormalizeReturnUrl(returnUrl);
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpControllerBase.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpControllerBase.cs
index d890c3a9f6..e37ef18f0c 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpControllerBase.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpControllerBase.cs
@@ -22,11 +22,11 @@ namespace Volo.Abp.AspNetCore.Mvc;
 
 public abstract class AbpControllerBase : ControllerBase, IAvoidDuplicateCrossCuttingConcerns
 {
-    public IAbpLazyServiceProvider LazyServiceProvider { get; set; }
+    public IAbpLazyServiceProvider LazyServiceProvider { get; set; } = default!;
 
     protected IUnitOfWorkManager UnitOfWorkManager => LazyServiceProvider.LazyGetRequiredService<IUnitOfWorkManager>();
 
-    protected Type ObjectMapperContext { get; set; }
+    protected Type? ObjectMapperContext { get; set; }
     protected IObjectMapper ObjectMapper => LazyServiceProvider.LazyGetService<IObjectMapper>(provider =>
         ObjectMapperContext == null
             ? provider.GetRequiredService<IObjectMapper>()
@@ -36,7 +36,7 @@ public abstract class AbpControllerBase : ControllerBase, IAvoidDuplicateCrossCu
 
     protected ILoggerFactory LoggerFactory => LazyServiceProvider.LazyGetRequiredService<ILoggerFactory>();
 
-    protected ILogger Logger => LazyServiceProvider.LazyGetService<ILogger>(provider => LoggerFactory?.CreateLogger(GetType().FullName) ?? NullLogger.Instance);
+    protected ILogger Logger => LazyServiceProvider.LazyGetService<ILogger>(provider => LoggerFactory?.CreateLogger(GetType().FullName!) ?? NullLogger.Instance);
 
     protected ICurrentUser CurrentUser => LazyServiceProvider.LazyGetRequiredService<ICurrentUser>();
 
@@ -44,7 +44,7 @@ public abstract class AbpControllerBase : ControllerBase, IAvoidDuplicateCrossCu
 
     protected IAuthorizationService AuthorizationService => LazyServiceProvider.LazyGetRequiredService<IAuthorizationService>();
 
-    protected IUnitOfWork CurrentUnitOfWork => UnitOfWorkManager?.Current;
+    protected IUnitOfWork? CurrentUnitOfWork => UnitOfWorkManager?.Current;
 
     protected IClock Clock => LazyServiceProvider.LazyGetRequiredService<IClock>();
 
@@ -64,16 +64,16 @@ public abstract class AbpControllerBase : ControllerBase, IAvoidDuplicateCrossCu
             return _localizer;
         }
     }
-    private IStringLocalizer _localizer;
+    private IStringLocalizer? _localizer;
 
-    protected Type LocalizationResource {
+    protected Type? LocalizationResource {
         get => _localizationResource;
         set {
             _localizationResource = value;
             _localizer = null;
         }
     }
-    private Type _localizationResource = typeof(DefaultResource);
+    private Type? _localizationResource = typeof(DefaultResource);
 
     public List<string> AppliedCrossCuttingConcerns { get; } = new List<string>();
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpDataAnnotationAutoLocalizationMetadataDetailsProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpDataAnnotationAutoLocalizationMetadataDetailsProvider.cs
index cb0d9547a2..badeeb8edd 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpDataAnnotationAutoLocalizationMetadataDetailsProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpDataAnnotationAutoLocalizationMetadataDetailsProvider.cs
@@ -17,13 +17,13 @@ public class AbpDataAnnotationAutoLocalizationMetadataDetailsProvider : IDisplay
 
     private readonly Lazy<IStringLocalizerFactory> _stringLocalizerFactory;
     private readonly Lazy<IOptions<MvcDataAnnotationsLocalizationOptions>> _localizationOptions;
-    private readonly ConcurrentDictionary<DisplayMetadataProviderContext, string> _displayNameKeys;
+    private readonly ConcurrentDictionary<DisplayMetadataProviderContext, string?> _displayNameKeys;
 
     public AbpDataAnnotationAutoLocalizationMetadataDetailsProvider(IServiceCollection services)
     {
         _stringLocalizerFactory = services.GetRequiredServiceLazy<IStringLocalizerFactory>();
         _localizationOptions = services.GetRequiredServiceLazy<IOptions<MvcDataAnnotationsLocalizationOptions>>();
-        _displayNameKeys = new ConcurrentDictionary<DisplayMetadataProviderContext, string>();
+        _displayNameKeys = new ConcurrentDictionary<DisplayMetadataProviderContext, string?>();
     }
 
     public virtual void CreateDisplayMetadata(DisplayMetadataProviderContext context)
@@ -58,11 +58,11 @@ public class AbpDataAnnotationAutoLocalizationMetadataDetailsProvider : IDisplay
         displayMetadata.DisplayName = () =>
         {
             var key = _displayNameKeys.GetOrAdd(context, _ => GetDisplayNameKey(context, localizer));
-            return key != null ? localizer[key] : null;
+            return (key != null ? localizer[key] : null)!;
         };
     }
 
-    protected virtual string GetDisplayNameKey(DisplayMetadataProviderContext context, IStringLocalizer localizer)
+    protected virtual string? GetDisplayNameKey(DisplayMetadataProviderContext context, IStringLocalizer localizer)
     {
         /*
         * DisplayName:ClassName:PropertyName
@@ -71,7 +71,7 @@ public class AbpDataAnnotationAutoLocalizationMetadataDetailsProvider : IDisplay
         * PropertyName
         */
 
-        LocalizedString localizedString = null;
+        LocalizedString? localizedString = null;
 
         if (context.Key.ContainerType != null)
         {
@@ -102,7 +102,7 @@ public class AbpDataAnnotationAutoLocalizationMetadataDetailsProvider : IDisplay
 
         if (localizedString.ResourceNotFound)
         {
-            localizedString = localizer[context.Key.Name];
+            localizedString = localizer[context.Key.Name!];
             if (!localizedString.ResourceNotFound)
             {
                 return localizedString.Name;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpViewComponent.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpViewComponent.cs
index b8de0159f1..b628a39448 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpViewComponent.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AbpViewComponent.cs
@@ -8,12 +8,12 @@ namespace Volo.Abp.AspNetCore.Mvc;
 
 public abstract class AbpViewComponent : ViewComponent
 {
-    public IAbpLazyServiceProvider LazyServiceProvider { get; set; }
+    public IAbpLazyServiceProvider LazyServiceProvider { get; set; } = default!;
 
     [Obsolete("Use LazyServiceProvider instead.")]
-    public IServiceProvider ServiceProvider { get; set; }
+    public IServiceProvider ServiceProvider { get; set; } = default!;
 
-    protected Type ObjectMapperContext { get; set; }
+    protected Type? ObjectMapperContext { get; set; }
 
     protected IObjectMapper ObjectMapper => LazyServiceProvider.LazyGetService<IObjectMapper>(provider =>
         ObjectMapperContext == null
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AbpAntiForgeryCookieNameProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AbpAntiForgeryCookieNameProvider.cs
index b56ed8ac24..9fa1fc1554 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AbpAntiForgeryCookieNameProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AbpAntiForgeryCookieNameProvider.cs
@@ -17,7 +17,7 @@ public class AbpAntiForgeryCookieNameProvider : ITransientDependency
         _abpAntiForgeryOptions = abpAntiForgeryOptions.Value;
     }
 
-    public virtual string GetAuthCookieNameOrNull()
+    public virtual string? GetAuthCookieNameOrNull()
     {
         if (_abpAntiForgeryOptions.AuthCookieSchemaName == null)
         {
@@ -27,7 +27,7 @@ public class AbpAntiForgeryCookieNameProvider : ITransientDependency
         return _namedOptionsAccessor.Get(_abpAntiForgeryOptions.AuthCookieSchemaName)?.Cookie?.Name;
     }
 
-    public virtual string GetAntiForgeryCookieNameOrNull()
+    public virtual string? GetAntiForgeryCookieNameOrNull()
     {
         return _abpAntiForgeryOptions.TokenCookie.Name;
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AbpAntiForgeryOptions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AbpAntiForgeryOptions.cs
index ba577027a9..0c2cf8884c 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AbpAntiForgeryOptions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AbpAntiForgeryOptions.cs
@@ -17,7 +17,7 @@ public class AbpAntiForgeryOptions
     /// Used to find auth cookie when validating Anti Forgery token.
     /// Default value: "Identity.Application".
     /// </summary>
-    public string AuthCookieSchemaName { get; set; }
+    public string? AuthCookieSchemaName { get; set; }
 
     /// <summary>
     /// Default value: true.
@@ -34,7 +34,7 @@ public class AbpAntiForgeryOptions
         get => _autoValidateFilter;
         set => _autoValidateFilter = Check.NotNull(value, nameof(value));
     }
-    private Predicate<Type> _autoValidateFilter;
+    private Predicate<Type> _autoValidateFilter = default!;
 
     /// <summary>
     /// Default methods: "GET", "HEAD", "TRACE", "OPTIONS".
@@ -44,7 +44,7 @@ public class AbpAntiForgeryOptions
         get => _autoValidateIgnoredHttpMethods;
         set => _autoValidateIgnoredHttpMethods = Check.NotNull(value, nameof(value));
     }
-    private HashSet<string> _autoValidateIgnoredHttpMethods;
+    private HashSet<string> _autoValidateIgnoredHttpMethods = default!;
 
     public AbpAntiForgeryOptions()
     {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AspNetCoreAbpAntiForgeryManager.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AspNetCoreAbpAntiForgeryManager.cs
index 27aa9a0a58..b13fe68508 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AspNetCoreAbpAntiForgeryManager.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AntiForgery/AspNetCoreAbpAntiForgeryManager.cs
@@ -9,7 +9,7 @@ public class AspNetCoreAbpAntiForgeryManager : IAbpAntiForgeryManager, ITransien
 {
     protected AbpAntiForgeryOptions Options { get; }
 
-    protected HttpContext HttpContext => _httpContextAccessor.HttpContext;
+    protected HttpContext HttpContext => _httpContextAccessor.HttpContext!;
 
     private readonly IAntiforgery _antiforgery;
     private readonly IHttpContextAccessor _httpContextAccessor;
@@ -27,7 +27,7 @@ public class AspNetCoreAbpAntiForgeryManager : IAbpAntiForgeryManager, ITransien
     public virtual void SetCookie()
     {
         HttpContext.Response.Cookies.Append(
-            Options.TokenCookie.Name,
+            Options.TokenCookie.Name!,
             GenerateToken(),
             Options.TokenCookie.Build(HttpContext)
         );
@@ -35,6 +35,6 @@ public class AspNetCoreAbpAntiForgeryManager : IAbpAntiForgeryManager, ITransien
 
     public virtual string GenerateToken()
     {
-        return _antiforgery.GetAndStoreTokens(_httpContextAccessor.HttpContext).RequestToken;
+        return _antiforgery.GetAndStoreTokens(_httpContextAccessor.HttpContext!).RequestToken!;
     }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApiExploring/AbpRemoteServiceApiDescriptionProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApiExploring/AbpRemoteServiceApiDescriptionProvider.cs
index 23cc2e155d..b8d98d7de4 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApiExploring/AbpRemoteServiceApiDescriptionProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApiExploring/AbpRemoteServiceApiDescriptionProvider.cs
@@ -62,11 +62,11 @@ public class AbpRemoteServiceApiDescriptionProvider : IApiDescriptionProvider, I
     {
         foreach (var apiResponse in _options.SupportedResponseTypes)
         {
-            apiResponse.ModelMetadata = _modelMetadataProvider.GetMetadataForType(apiResponse.Type);
+            apiResponse.ModelMetadata = _modelMetadataProvider.GetMetadataForType(apiResponse.Type!);
 
             foreach (var responseTypeMetadataProvider in _mvcOptions.OutputFormatters.OfType<IApiResponseTypeMetadataProvider>())
             {
-                var formatterSupportedContentTypes = responseTypeMetadataProvider.GetSupportedContentTypes(null, apiResponse.Type);
+                var formatterSupportedContentTypes = responseTypeMetadataProvider.GetSupportedContentTypes(null!, apiResponse.Type!);
                 if (formatterSupportedContentTypes == null)
                 {
                     continue;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/AbpApplicationConfigurationAppService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/AbpApplicationConfigurationAppService.cs
index 4254b5479f..e15bc7c136 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/AbpApplicationConfigurationAppService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/AbpApplicationConfigurationAppService.cs
@@ -127,7 +127,7 @@ public class AbpApplicationConfigurationAppService : ApplicationService, IAbpApp
         return new CurrentTenantDto()
         {
             Id = CurrentTenant.Id,
-            Name = CurrentTenant.Name,
+            Name = CurrentTenant.Name!,
             IsAvailable = CurrentTenant.IsAvailable
         };
     }
@@ -286,7 +286,7 @@ public class AbpApplicationConfigurationAppService : ApplicationService, IAbpApp
     {
         var result = new ApplicationSettingConfigurationDto
         {
-            Values = new Dictionary<string, string>()
+            Values = new Dictionary<string, string?>()
         };
 
         var settingDefinitions = _settingDefinitionManager.GetAll().Where(x => x.IsVisibleToClients);
@@ -346,7 +346,7 @@ public class AbpApplicationConfigurationAppService : ApplicationService, IAbpApp
                 {
                     TimeZoneName = windowsTimeZoneId.IsNullOrWhiteSpace()
                         ? null
-                        : _timezoneProvider.WindowsToIana(windowsTimeZoneId)
+                        : _timezoneProvider.WindowsToIana(windowsTimeZoneId!)
                 }
             }
         };
@@ -356,7 +356,7 @@ public class AbpApplicationConfigurationAppService : ApplicationService, IAbpApp
     {
         return new ClockDto
         {
-            Kind = Enum.GetName(typeof(DateTimeKind), _abpClockOptions.Kind)
+            Kind = Enum.GetName(typeof(DateTimeKind), _abpClockOptions.Kind)!
         };
     }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/AbpApplicationLocalizationAppService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/AbpApplicationLocalizationAppService.cs
index 58eefeba5e..4cf03c0b4a 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/AbpApplicationLocalizationAppService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/AbpApplicationLocalizationAppService.cs
@@ -50,7 +50,7 @@ public class AbpApplicationLocalizationAppService :
                 var localizer = await StringLocalizerFactory.CreateByResourceNameOrNullAsync(resource.ResourceName);
                 if (localizer != null)
                 {
-                    Dictionary<string, LocalizedString> staticLocalizedStrings = null;
+                    Dictionary<string, LocalizedString>? staticLocalizedStrings = null;
                     
                     if (input.OnlyDynamics)
                     {
@@ -71,7 +71,7 @@ public class AbpApplicationLocalizationAppService :
                     {
                         if (input.OnlyDynamics)
                         {
-                            var staticLocalizedString = staticLocalizedStrings.GetOrDefault(localizedString.Name);
+                            var staticLocalizedString = staticLocalizedStrings!.GetOrDefault(localizedString.Name);
                             if (staticLocalizedString != null &&
                                 localizedString.Value == staticLocalizedString.Value)
                             {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/CachedObjectExtensionsDtoService.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/CachedObjectExtensionsDtoService.cs
index 0f9b05830d..66232802c0 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/CachedObjectExtensionsDtoService.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/CachedObjectExtensionsDtoService.cs
@@ -12,7 +12,7 @@ namespace Volo.Abp.AspNetCore.Mvc.ApplicationConfigurations.ObjectExtending;
 public class CachedObjectExtensionsDtoService : ICachedObjectExtensionsDtoService, ISingletonDependency
 {
     protected IExtensionPropertyAttributeDtoFactory ExtensionPropertyAttributeDtoFactory { get; }
-    protected volatile ObjectExtensionsDto CachedValue;
+    protected volatile ObjectExtensionsDto? CachedValue;
     protected readonly object SyncLock = new object();
 
     public CachedObjectExtensionsDtoService(IExtensionPropertyAttributeDtoFactory extensionPropertyAttributeDtoFactory)
@@ -193,7 +193,7 @@ public class CachedObjectExtensionsDtoService : ICachedObjectExtensionsDtoServic
         return TypeHelper.GetSimplifiedName(propertyConfig.Type);
     }
 
-    protected virtual LocalizableStringDto CreateDisplayNameDto(ExtensionPropertyConfiguration propertyConfig)
+    protected virtual LocalizableStringDto? CreateDisplayNameDto(ExtensionPropertyConfiguration propertyConfig)
     {
         if (propertyConfig.DisplayName == null)
         {
@@ -231,7 +231,7 @@ public class CachedObjectExtensionsDtoService : ICachedObjectExtensionsDtoServic
         foreach (var enumProperty in enumProperties)
         {
             // ReSharper disable once AssignNullToNotNullAttribute (enumProperty.Type.FullName can not be null for this case)
-            objectExtensionsDto.Enums[enumProperty.Type.FullName] = CreateExtensionEnumDto(enumProperty);
+            objectExtensionsDto.Enums[enumProperty.Type.FullName!] = CreateExtensionEnumDto(enumProperty);
         }
     }
 
@@ -248,7 +248,7 @@ public class CachedObjectExtensionsDtoService : ICachedObjectExtensionsDtoServic
             extensionEnumDto.Fields.Add(
                 new ExtensionEnumFieldDto
                 {
-                    Name = enumProperty.Type.GetEnumName(enumValue),
+                    Name = enumProperty.Type.GetEnumName(enumValue)!,
                     Value = enumValue
                 }
             );
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyAttributeDtoFactory.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyAttributeDtoFactory.cs
index 2fb94d9930..742cab75ea 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyAttributeDtoFactory.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationConfigurations/ObjectExtending/ExtensionPropertyAttributeDtoFactory.cs
@@ -71,7 +71,7 @@ public class ExtensionPropertyAttributeDtoFactory : IExtensionPropertyAttributeD
         return false;
     }
 
-    protected virtual object GetPropertyValue(Attribute attribute, PropertyInfo property)
+    protected virtual object? GetPropertyValue(Attribute attribute, PropertyInfo property)
     {
         var value = property.GetValue(attribute);
         if (value == null)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationPartSorter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationPartSorter.cs
index dc39ef5f53..9bc15ae617 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationPartSorter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ApplicationPartSorter.cs
@@ -135,7 +135,7 @@ public static class ApplicationPartSorter
             .ToArray();
     }
 
-    private static CompiledRazorAssemblyPart GetViewsPartOrNull(ApplicationPartManager partManager,
+    private static CompiledRazorAssemblyPart? GetViewsPartOrNull(ApplicationPartManager partManager,
         ApplicationPart assemblyPart)
     {
         var viewsAssemblyName = assemblyPart.Name + ".Views";
@@ -145,7 +145,7 @@ public static class ApplicationPartSorter
             .FirstOrDefault(p => p.Name == viewsAssemblyName);
     }
 
-    private static AssemblyPart GetOriginalAssemblyPartOrNull(
+    private static AssemblyPart? GetOriginalAssemblyPartOrNull(
         CompiledRazorAssemblyPart compiledRazorAssemblyPart,
         ApplicationPartManager partManager)
     {
@@ -155,7 +155,7 @@ public static class ApplicationPartSorter
             .FirstOrDefault(p => p.Name == originalAssemblyName);
     }
 
-    private static IAbpModuleDescriptor GetModuleDescriptorForAssemblyOrNull(
+    private static IAbpModuleDescriptor? GetModuleDescriptorForAssemblyOrNull(
         IModuleContainer moduleContainer,
         Assembly assembly)
     {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProvider.cs
index f18e9d6c3c..9e3b0bfba2 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProvider.cs
@@ -162,7 +162,7 @@ public class AspNetCoreApiDescriptionModelProvider : IApiDescriptionModelProvide
     }
 
     private static List<string> GetSupportedVersions(Type controllerType, MethodInfo method,
-        ConventionalControllerSetting setting)
+        ConventionalControllerSetting? setting)
     {
         var supportedVersions = new List<ApiVersion>();
 
@@ -196,7 +196,7 @@ public class AspNetCoreApiDescriptionModelProvider : IApiDescriptionModelProvide
     }
 
     private static void AddCustomTypesToModel(ApplicationApiDescriptionModel applicationModel,
-        [CanBeNull] Type type)
+        Type? type)
     {
         if (type == null)
         {
@@ -275,7 +275,7 @@ public class AspNetCoreApiDescriptionModelProvider : IApiDescriptionModelProvide
             .Select(_ => "T" + i++)
             .JoinAsString(",");
 
-        return $"{type.FullName.Left(type.FullName.IndexOf('`'))}<{argumentList}>";
+        return $"{type.FullName!.Left(type.FullName!.IndexOf('`'))}<{argumentList}>";
     }
 
     private void AddParameterDescriptionsToModel(ActionApiDescriptionModel actionModel, MethodInfo method,
@@ -339,16 +339,16 @@ public class AspNetCoreApiDescriptionModelProvider : IApiDescriptionModelProvide
 
         if (modelNameProvider == null)
         {
-            return parameterInfo.Name;
+            return parameterInfo.Name!;
         }
 
-        return modelNameProvider.Name ?? parameterInfo.Name;
+        return (modelNameProvider.Name ?? parameterInfo.Name)!;
     }
 
     private static string GetRootPath(
         [NotNull] Type controllerType,
         [NotNull] ActionDescriptor actionDescriptor,
-        [CanBeNull] ConventionalControllerSetting setting)
+        ConventionalControllerSetting? setting)
     {
         if (setting != null)
         {
@@ -364,7 +364,7 @@ public class AspNetCoreApiDescriptionModelProvider : IApiDescriptionModelProvide
         return ModuleApiDescriptionModel.DefaultRootPath;
     }
 
-    private string GetRemoteServiceName(Type controllerType, [CanBeNull] ConventionalControllerSetting setting)
+    private string GetRemoteServiceName(Type controllerType, ConventionalControllerSetting? setting)
     {
         if (setting != null)
         {
@@ -381,7 +381,7 @@ public class AspNetCoreApiDescriptionModelProvider : IApiDescriptionModelProvide
         return ModuleApiDescriptionModel.DefaultRemoteServiceName;
     }
 
-    private string FindGroupName(Type controllerType)
+    private string? FindGroupName(Type controllerType)
     {
         var controllerNameAttribute =
             controllerType.GetCustomAttributes().OfType<ControllerNameAttribute>().FirstOrDefault();
@@ -394,8 +394,7 @@ public class AspNetCoreApiDescriptionModelProvider : IApiDescriptionModelProvide
         return null;
     }
 
-    [CanBeNull]
-    private ConventionalControllerSetting FindSetting(Type controllerType)
+    private ConventionalControllerSetting? FindSetting(Type controllerType)
     {
         foreach (var controllerSetting in _abpAspNetCoreMvcOptions.ConventionalControllers.ConventionalControllerSettings)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProviderOptions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProviderOptions.cs
index 4dc4a9719a..8446336053 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProviderOptions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/AspNetCoreApiDescriptionModelProviderOptions.cs
@@ -12,11 +12,11 @@ namespace Volo.Abp.AspNetCore.Mvc;
 
 public class AspNetCoreApiDescriptionModelProviderOptions
 {
-    public Func<Type, ConventionalControllerSetting, string> ControllerNameGenerator { get; set; }
+    public Func<Type, ConventionalControllerSetting?, string> ControllerNameGenerator { get; set; }
 
     public Func<MethodInfo, string> ActionNameGenerator { get; set; }
 
-    public Func<ApiParameterDescription, string> ApiParameterNameGenerator { get; set; }
+    public Func<ApiParameterDescription, string?> ApiParameterNameGenerator { get; set; }
 
     public AspNetCoreApiDescriptionModelProviderOptions()
     {
@@ -51,7 +51,7 @@ public class AspNetCoreApiDescriptionModelProviderOptions
                         methodNameBuilder.Append("And");
                     }
 
-                    methodNameBuilder.Append(parameters[i].Name.ToPascalCase());
+                    methodNameBuilder.Append(parameters[i].Name!.ToPascalCase());
                 }
             }
 
@@ -62,7 +62,7 @@ public class AspNetCoreApiDescriptionModelProviderOptions
         {
             if (apiParameterDescription.ModelMetadata is DefaultModelMetadata defaultModelMetadata)
             {
-                var jsonPropertyNameAttribute = (JsonPropertyNameAttribute)
+                var jsonPropertyNameAttribute = (JsonPropertyNameAttribute?)
                     defaultModelMetadata?.Attributes?.PropertyAttributes?.FirstOrDefault(x => x is JsonPropertyNameAttribute);
                 if (jsonPropertyNameAttribute != null)
                 {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Auditing/AbpAuditActionFilter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Auditing/AbpAuditActionFilter.cs
index 82105693ec..07101da0cb 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Auditing/AbpAuditActionFilter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Auditing/AbpAuditActionFilter.cs
@@ -30,12 +30,12 @@ public class AbpAuditActionFilter : IAsyncActionFilter, ITransientDependency
 
                 if (result.Exception != null && !result.ExceptionHandled)
                 {
-                    auditLog.Exceptions.Add(result.Exception);
+                    auditLog!.Exceptions.Add(result.Exception);
                 }
             }
             catch (Exception ex)
             {
-                auditLog.Exceptions.Add(ex);
+                auditLog!.Exceptions.Add(ex);
                 throw;
             }
             finally
@@ -45,13 +45,13 @@ public class AbpAuditActionFilter : IAsyncActionFilter, ITransientDependency
                 if (auditLogAction != null)
                 {
                     auditLogAction.ExecutionDuration = Convert.ToInt32(stopwatch.Elapsed.TotalMilliseconds);
-                    auditLog.Actions.Add(auditLogAction);
+                    auditLog!.Actions.Add(auditLogAction);
                 }
             }
         }
     }
 
-    private bool ShouldSaveAudit(ActionExecutingContext context, out AuditLogInfo auditLog, out AuditLogActionInfo auditLogAction)
+    private bool ShouldSaveAudit(ActionExecutingContext context, out AuditLogInfo? auditLog, out AuditLogActionInfo? auditLogAction)
     {
         auditLog = null;
         auditLogAction = null;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Auditing/AbpAuditPageFilter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Auditing/AbpAuditPageFilter.cs
index 51137d3812..8445be60ae 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Auditing/AbpAuditPageFilter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Auditing/AbpAuditPageFilter.cs
@@ -35,12 +35,12 @@ public class AbpAuditPageFilter : IAsyncPageFilter, ITransientDependency
 
                 if (result.Exception != null && !result.ExceptionHandled)
                 {
-                    auditLog.Exceptions.Add(result.Exception);
+                    auditLog!.Exceptions.Add(result.Exception);
                 }
             }
             catch (Exception ex)
             {
-                auditLog.Exceptions.Add(ex);
+                auditLog!.Exceptions.Add(ex);
                 throw;
             }
             finally
@@ -50,13 +50,13 @@ public class AbpAuditPageFilter : IAsyncPageFilter, ITransientDependency
                 if (auditLogAction != null)
                 {
                     auditLogAction.ExecutionDuration = Convert.ToInt32(stopwatch.Elapsed.TotalMilliseconds);
-                    auditLog.Actions.Add(auditLogAction);
+                    auditLog!.Actions.Add(auditLogAction);
                 }
             }
         }
     }
 
-    private bool ShouldSaveAudit(PageHandlerExecutingContext context, out AuditLogInfo auditLog, out AuditLogActionInfo auditLogAction)
+    private bool ShouldSaveAudit(PageHandlerExecutingContext context, out AuditLogInfo? auditLog, out AuditLogActionInfo? auditLogAction)
     {
         auditLog = null;
         auditLogAction = null;
@@ -79,7 +79,7 @@ public class AbpAuditPageFilter : IAsyncPageFilter, ITransientDependency
         }
 
         var auditingHelper = context.GetRequiredService<IAuditingHelper>();
-        if (!auditingHelper.ShouldSaveAudit(context.HandlerMethod.MethodInfo, defaultValue: true))
+        if (!auditingHelper.ShouldSaveAudit(context.HandlerMethod!.MethodInfo, defaultValue: true))
         {
             return false;
         }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Authentication/ChallengeAccountController.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Authentication/ChallengeAccountController.cs
index 15abd26b1e..802dad66f2 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Authentication/ChallengeAccountController.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Authentication/ChallengeAccountController.cs
@@ -14,7 +14,7 @@ public abstract class ChallengeAccountController : AbpController
     protected string AuthenticationType { get; }
     protected string[] ForbidSchemes { get; }
 
-    protected ChallengeAccountController(string[] challengeAuthenticationSchemas = null)
+    protected ChallengeAccountController(string[]? challengeAuthenticationSchemas = null)
     {
         ChallengeAuthenticationSchemas = challengeAuthenticationSchemas ?? new[] { "oidc" };
         AuthenticationType = "Identity.Application";
@@ -68,12 +68,12 @@ public abstract class ChallengeAccountController : AbpController
             {
                 RedirectUri = GetRedirectUrl(returnUrl, returnUrlHash)
             },
-            ForbidSchemes.IsNullOrEmpty()
+            (ForbidSchemes.IsNullOrEmpty()
                 ? new[]
                 {
                     HttpContext.RequestServices.GetRequiredService<IOptions<AuthenticationOptions>>().Value.DefaultForbidScheme
                 }
-                : ForbidSchemes
+                : ForbidSchemes)!
         ));
     }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/AbpRemoteStreamContentModelBinder.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/AbpRemoteStreamContentModelBinder.cs
index ea633f569a..2cc051ba62 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/AbpRemoteStreamContentModelBinder.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/AbpRemoteStreamContentModelBinder.cs
@@ -155,6 +155,6 @@ public class AbpRemoteStreamContentModelBinder<TRemoteStreamContent> : IModelBin
             return new List<T>();
         }
 
-        return (ICollection<T>)Activator.CreateInstance(modelType);
+        return (ICollection<T>)Activator.CreateInstance(modelType)!;
     }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/AbpRemoteStreamContentModelBinderProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/AbpRemoteStreamContentModelBinderProvider.cs
index 7892e6a1c2..83a31c792e 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/AbpRemoteStreamContentModelBinderProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/AbpRemoteStreamContentModelBinderProvider.cs
@@ -7,7 +7,7 @@ namespace Volo.Abp.AspNetCore.Mvc.ContentFormatters;
 
 public class AbpRemoteStreamContentModelBinderProvider : IModelBinderProvider
 {
-    public IModelBinder GetBinder(ModelBinderProviderContext context)
+    public IModelBinder? GetBinder(ModelBinderProviderContext context)
     {
         if (context == null)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/RemoteStreamContentOutputFormatter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/RemoteStreamContentOutputFormatter.cs
index e41616617d..5bba1b386a 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/RemoteStreamContentOutputFormatter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ContentFormatters/RemoteStreamContentOutputFormatter.cs
@@ -13,14 +13,14 @@ public class RemoteStreamContentOutputFormatter : OutputFormatter
         SupportedMediaTypes.Add(MediaTypeHeaderValue.Parse("*/*"));
     }
 
-    protected override bool CanWriteType(Type type)
+    protected override bool CanWriteType(Type? type)
     {
         return typeof(IRemoteStreamContent).IsAssignableFrom(type);
     }
 
     public async override Task WriteResponseBodyAsync(OutputFormatterWriteContext context)
     {
-        var remoteStream = (IRemoteStreamContent)context.Object;
+        var remoteStream = (IRemoteStreamContent?)context.Object;
 
         if (remoteStream != null)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/AbpConventionalControllerOptions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/AbpConventionalControllerOptions.cs
index 1d508fb778..1b8e7fcb1b 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/AbpConventionalControllerOptions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/AbpConventionalControllerOptions.cs
@@ -33,7 +33,7 @@ public class AbpConventionalControllerOptions
 
     public AbpConventionalControllerOptions Create(
         Assembly assembly,
-        [CanBeNull] Action<ConventionalControllerSetting> optionsAction = null)
+        Action<ConventionalControllerSetting>? optionsAction = null)
     {
         var setting = new ConventionalControllerSetting(
             assembly,
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/AbpServiceConvention.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/AbpServiceConvention.cs
index 19479f552d..ba85a34f65 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/AbpServiceConvention.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/AbpServiceConvention.cs
@@ -105,7 +105,7 @@ public class AbpServiceConvention : IAbpServiceConvention, ITransientDependency
             if (removeControllerModels.Any())
             {
                 controllerModelsToRemove.AddRange(removeControllerModels);
-                Logger.LogInformation($"Removing the controller{(removeControllerModels.Length > 1 ? "s" : "")} {removeControllerModels.Select(c => c.ControllerType.AssemblyQualifiedName).JoinAsString(", ")} from the application model");
+                Logger.LogInformation($"Removing the controller{(removeControllerModels.Length > 1 ? "s" : "")} {removeControllerModels.Select(c => c.ControllerType.AssemblyQualifiedName)!.JoinAsString(", ")} from the application model");
             }
         }
 
@@ -121,7 +121,7 @@ public class AbpServiceConvention : IAbpServiceConvention, ITransientDependency
                 if (replaceControllerModels.Any())
                 {
                     controllerModelsToRemove.AddRange(replaceControllerModels);
-                    Logger.LogInformation($"Removing the controller{(replaceControllerModels.Length > 1 ? "s" : "")} {replaceControllersAttr.ControllerTypes.Select(c => c.AssemblyQualifiedName).JoinAsString(", ")} from the application model since {(replaceControllerModels.Length > 1 ? "they are" : "it is")} replaced by the controller: {controllerModel.ControllerType.AssemblyQualifiedName}");
+                    Logger.LogInformation($"Removing the controller{(replaceControllerModels.Length > 1 ? "s" : "")} {replaceControllersAttr.ControllerTypes.Select(c => c.AssemblyQualifiedName)!.JoinAsString(", ")} from the application model since {(replaceControllerModels.Length > 1 ? "they are" : "it is")} replaced by the controller: {controllerModel.ControllerType.AssemblyQualifiedName}");
                 }
             }
         }
@@ -139,7 +139,7 @@ public class AbpServiceConvention : IAbpServiceConvention, ITransientDependency
             }
 
             var exposeServicesAttr = ReflectionHelper.GetSingleAttributeOrDefault<ExposeServicesAttribute>(controllerModel.ControllerType);
-            if (exposeServicesAttr.IncludeSelf)
+            if (exposeServicesAttr!.IncludeSelf)
             {
                 var exposedControllerModels = GetControllers(application)
                     .Where(cm => exposeServicesAttr.ServiceTypes.Contains(cm.ControllerType))
@@ -148,7 +148,7 @@ public class AbpServiceConvention : IAbpServiceConvention, ITransientDependency
                 if (exposedControllerModels.Any())
                 {
                     controllerModelsToRemove.AddRange(exposedControllerModels);
-                    Logger.LogInformation($"Removing the controller{(exposedControllerModels.Length > 1 ? "s" : "")} {exposeServicesAttr.ServiceTypes.Select(c => c.AssemblyQualifiedName).JoinAsString(", ")} from the application model since {(exposedControllerModels.Length > 1 ? "they are" : "it is")} replaced by the controller: {controllerModel.ControllerType.AssemblyQualifiedName}");
+                    Logger.LogInformation($"Removing the controller{(exposedControllerModels.Length > 1 ? "s" : "")} {exposeServicesAttr.ServiceTypes.Select(c => c.AssemblyQualifiedName)!.JoinAsString(", ")} from the application model since {(exposedControllerModels.Length > 1 ? "they are" : "it is")} replaced by the controller: {controllerModel.ControllerType.AssemblyQualifiedName}");
                 }
                 continue;
             }
@@ -173,13 +173,13 @@ public class AbpServiceConvention : IAbpServiceConvention, ITransientDependency
             }
 
             controllerModelsToRemove.Add(controllerModel);
-            Logger.LogInformation($"Removing the controller {controllerModel.ControllerType.AssemblyQualifiedName} from the application model since it replaces the controller(s): {baseControllerTypes.Select(c => c.AssemblyQualifiedName).JoinAsString(", ")}");
+            Logger.LogInformation($"Removing the controller {controllerModel.ControllerType.AssemblyQualifiedName} from the application model since it replaces the controller(s): {baseControllerTypes.Select(c => c.AssemblyQualifiedName)!.JoinAsString(", ")}");
         }
 
         application.Controllers.RemoveAll(controllerModelsToRemove);
     }
 
-    protected virtual void ConfigureRemoteService(ControllerModel controller, [CanBeNull] ConventionalControllerSetting configuration)
+    protected virtual void ConfigureRemoteService(ControllerModel controller, ConventionalControllerSetting? configuration)
     {
         ConfigureApiExplorer(controller);
         ConfigureSelector(controller, configuration);
@@ -288,7 +288,7 @@ public class AbpServiceConvention : IAbpServiceConvention, ITransientDependency
         action.ApiExplorer.IsVisible = visible;
     }
 
-    protected virtual void ConfigureSelector(ControllerModel controller, [CanBeNull] ConventionalControllerSetting configuration)
+    protected virtual void ConfigureSelector(ControllerModel controller, ConventionalControllerSetting? configuration)
     {
         RemoveEmptySelectors(controller.Selectors);
 
@@ -312,7 +312,7 @@ public class AbpServiceConvention : IAbpServiceConvention, ITransientDependency
         }
     }
 
-    protected virtual void ConfigureSelector(string rootPath, string controllerName, ActionModel action, [CanBeNull] ConventionalControllerSetting configuration)
+    protected virtual void ConfigureSelector(string rootPath, string controllerName, ActionModel action, ConventionalControllerSetting? configuration)
     {
         RemoveEmptySelectors(action.Selectors);
 
@@ -332,7 +332,7 @@ public class AbpServiceConvention : IAbpServiceConvention, ITransientDependency
         }
     }
 
-    protected virtual void AddAbpServiceSelector(string rootPath, string controllerName, ActionModel action, [CanBeNull] ConventionalControllerSetting configuration)
+    protected virtual void AddAbpServiceSelector(string rootPath, string controllerName, ActionModel action, ConventionalControllerSetting? configuration)
     {
         var httpMethod = SelectHttpMethod(action, configuration);
 
@@ -345,12 +345,12 @@ public class AbpServiceConvention : IAbpServiceConvention, ITransientDependency
         action.Selectors.Add(abpServiceSelectorModel);
     }
 
-    protected virtual string SelectHttpMethod(ActionModel action, ConventionalControllerSetting configuration)
+    protected virtual string SelectHttpMethod(ActionModel action, ConventionalControllerSetting? configuration)
     {
         return HttpMethodHelper.GetConventionalVerbForMethodName(action.ActionName);
     }
 
-    protected virtual void NormalizeSelectorRoutes(string rootPath, string controllerName, ActionModel action, [CanBeNull] ConventionalControllerSetting configuration)
+    protected virtual void NormalizeSelectorRoutes(string rootPath, string controllerName, ActionModel action, ConventionalControllerSetting? configuration)
     {
         foreach (var selector in action.Selectors)
         {
@@ -394,13 +394,12 @@ public class AbpServiceConvention : IAbpServiceConvention, ITransientDependency
         return ModuleApiDescriptionModel.DefaultRootPath;
     }
 
-    [CanBeNull]
-    protected virtual ConventionalControllerSetting GetControllerSettingOrNull(Type controllerType)
+    protected virtual ConventionalControllerSetting? GetControllerSettingOrNull(Type controllerType)
     {
         return Options.ConventionalControllers.ConventionalControllerSettings.GetSettingOrNull(controllerType);
     }
 
-    protected virtual AttributeRouteModel CreateAbpServiceAttributeRouteModel(string rootPath, string controllerName, ActionModel action, string httpMethod, [CanBeNull] ConventionalControllerSetting configuration)
+    protected virtual AttributeRouteModel CreateAbpServiceAttributeRouteModel(string rootPath, string controllerName, ActionModel action, string httpMethod, ConventionalControllerSetting? configuration)
     {
         return new AttributeRouteModel(
             new RouteAttribute(
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalControllerSetting.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalControllerSetting.cs
index bb059a6674..5523a52020 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalControllerSetting.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalControllerSetting.cs
@@ -33,7 +33,7 @@ public class ConventionalControllerSetting
             _rootPath = value;
         }
     }
-    private string _rootPath;
+    private string _rootPath = default!;
 
     [NotNull]
     public string RemoteServiceName {
@@ -43,28 +43,24 @@ public class ConventionalControllerSetting
             _remoteServiceName = value;
         }
     }
-    private string _remoteServiceName;
+    private string _remoteServiceName = default!;
 
-    [CanBeNull]
-    public Func<Type, bool> TypePredicate { get; set; }
+    public Func<Type, bool>? TypePredicate { get; set; }
 
     /// <summary>
     /// Default value: All.
     /// </summary>
     public ApplicationServiceTypes ApplicationServiceTypes { get; set; } = ApplicationServiceTypes.All;
 
-    [CanBeNull]
-    public Action<ControllerModel> ControllerModelConfigurer { get; set; }
+    public Action<ControllerModel>? ControllerModelConfigurer { get; set; }
 
-    [CanBeNull]
-    public Func<UrlControllerNameNormalizerContext, string> UrlControllerNameNormalizer { get; set; }
+    public Func<UrlControllerNameNormalizerContext, string>? UrlControllerNameNormalizer { get; set; }
 
-    [CanBeNull]
-    public Func<UrlActionNameNormalizerContext, string> UrlActionNameNormalizer { get; set; }
+    public Func<UrlActionNameNormalizerContext, string>? UrlActionNameNormalizer { get; set; }
 
     public List<ApiVersion> ApiVersions { get; }
 
-    public Action<ApiVersioningOptions> ApiVersionConfigurer { get; set; }
+    public Action<ApiVersioningOptions>? ApiVersionConfigurer { get; set; }
 
     public ConventionalControllerSetting(
         [NotNull] Assembly assembly,
@@ -84,7 +80,7 @@ public class ConventionalControllerSetting
         var types = Assembly.GetTypes()
             .Where(IsRemoteService)
             .Where(IsPreferredApplicationServiceType)
-            .WhereIf(TypePredicate != null, TypePredicate);
+            .WhereIf(TypePredicate != null, TypePredicate!);
 
         foreach (var type in types)
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalControllerSettingList.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalControllerSettingList.cs
index 085eef7163..633be5786f 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalControllerSettingList.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalControllerSettingList.cs
@@ -7,8 +7,7 @@ namespace Volo.Abp.AspNetCore.Mvc.Conventions;
 
 public class ConventionalControllerSettingList : List<ConventionalControllerSetting>
 {
-    [CanBeNull]
-    public ConventionalControllerSetting GetSettingOrNull(Type controllerType)
+    public ConventionalControllerSetting? GetSettingOrNull(Type controllerType)
     {
         return this.FirstOrDefault(controllerSetting => controllerSetting.ControllerTypes.Contains(controllerType));
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalRouteBuilder.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalRouteBuilder.cs
index f9c31467b5..7e5b364b3e 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalRouteBuilder.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/ConventionalRouteBuilder.cs
@@ -24,7 +24,7 @@ public class ConventionalRouteBuilder : IConventionalRouteBuilder, ITransientDep
         string controllerName,
         ActionModel action,
         string httpMethod,
-        [CanBeNull] ConventionalControllerSetting configuration)
+        ConventionalControllerSetting? configuration)
     {
         var apiRoutePrefix = GetApiRoutePrefix(action, configuration);
         var controllerNameInUrl =
@@ -71,7 +71,7 @@ public class ConventionalRouteBuilder : IConventionalRouteBuilder, ITransientDep
         return url;
     }
 
-    protected virtual string GetApiRoutePrefix(ActionModel actionModel, ConventionalControllerSetting configuration)
+    protected virtual string GetApiRoutePrefix(ActionModel actionModel, ConventionalControllerSetting? configuration)
     {
         if (IntegrationServiceAttribute.IsDefinedOrInherited(actionModel.Controller.ControllerType))
         {
@@ -82,7 +82,7 @@ public class ConventionalRouteBuilder : IConventionalRouteBuilder, ITransientDep
     }
 
     protected virtual string NormalizeUrlActionName(string rootPath, string controllerName, ActionModel action,
-        string httpMethod, [CanBeNull] ConventionalControllerSetting configuration)
+        string httpMethod, ConventionalControllerSetting? configuration)
     {
         var actionNameInUrl = HttpMethodHelper
             .RemoveHttpMethodPrefix(action.ActionName, httpMethod)
@@ -105,7 +105,7 @@ public class ConventionalRouteBuilder : IConventionalRouteBuilder, ITransientDep
     }
 
     protected virtual string NormalizeUrlControllerName(string rootPath, string controllerName, ActionModel action,
-        string httpMethod, [CanBeNull] ConventionalControllerSetting configuration)
+        string httpMethod, ConventionalControllerSetting? configuration)
     {
         if (configuration?.UrlControllerNameNormalizer == null)
         {
@@ -121,7 +121,7 @@ public class ConventionalRouteBuilder : IConventionalRouteBuilder, ITransientDep
     }
 
     protected virtual string NormalizeControllerNameCase(string controllerName,
-        [CanBeNull] ConventionalControllerSetting configuration)
+        ConventionalControllerSetting? configuration)
     {
         if (configuration?.UseV3UrlStyle ?? Options.UseV3UrlStyle)
         {
@@ -134,7 +134,7 @@ public class ConventionalRouteBuilder : IConventionalRouteBuilder, ITransientDep
     }
 
     protected virtual string NormalizeActionNameCase(string actionName,
-        [CanBeNull] ConventionalControllerSetting configuration)
+        ConventionalControllerSetting? configuration)
     {
         if (configuration?.UseV3UrlStyle ?? Options.UseV3UrlStyle)
         {
@@ -147,13 +147,13 @@ public class ConventionalRouteBuilder : IConventionalRouteBuilder, ITransientDep
     }
 
     protected virtual string NormalizeIdPropertyNameCase(PropertyInfo property,
-        [CanBeNull] ConventionalControllerSetting configuration)
+        ConventionalControllerSetting? configuration)
     {
         return property.Name;
     }
 
     protected virtual string NormalizeSecondaryIdNameCase(ParameterModel secondaryId,
-        [CanBeNull] ConventionalControllerSetting configuration)
+        ConventionalControllerSetting? configuration)
     {
         return secondaryId.ParameterName;
     }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/IConventionalRouteBuilder.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/IConventionalRouteBuilder.cs
index c1bac761ce..8e55911240 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/IConventionalRouteBuilder.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Conventions/IConventionalRouteBuilder.cs
@@ -10,6 +10,6 @@ public interface IConventionalRouteBuilder
         string controllerName,
         ActionModel action,
         string httpMethod,
-        [CanBeNull] ConventionalControllerSetting configuration
+        ConventionalControllerSetting? configuration
     );
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/AbpValidationAttributeAdapterProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/AbpValidationAttributeAdapterProvider.cs
index 466d8df630..0ba54c5448 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/AbpValidationAttributeAdapterProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/AbpValidationAttributeAdapterProvider.cs
@@ -14,7 +14,7 @@ public class AbpValidationAttributeAdapterProvider : IValidationAttributeAdapter
         _defaultAdapter = defaultAdapter;
     }
 
-    public virtual IAttributeAdapter GetAttributeAdapter(ValidationAttribute attribute, IStringLocalizer stringLocalizer)
+    public virtual IAttributeAdapter? GetAttributeAdapter(ValidationAttribute attribute, IStringLocalizer? stringLocalizer)
     {
         var type = attribute.GetType();
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicMaxLengthAttributeAdapter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicMaxLengthAttributeAdapter.cs
index 173931142d..37e4e40a4c 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicMaxLengthAttributeAdapter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicMaxLengthAttributeAdapter.cs
@@ -12,7 +12,7 @@ public class DynamicMaxLengthAttributeAdapter : AttributeAdapterBase<DynamicMaxL
 
     public DynamicMaxLengthAttributeAdapter(
         DynamicMaxLengthAttribute attribute,
-        IStringLocalizer stringLocalizer)
+        IStringLocalizer? stringLocalizer)
         : base(attribute, stringLocalizer)
     {
         _max = Attribute.Length.ToString(CultureInfo.InvariantCulture);
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicRangeAttributeAdapter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicRangeAttributeAdapter.cs
index c0631645f0..6ecb54ec96 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicRangeAttributeAdapter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicRangeAttributeAdapter.cs
@@ -14,11 +14,11 @@ public class DynamicRangeAttributeAdapter : AttributeAdapterBase<DynamicRangeAtt
 
     public DynamicRangeAttributeAdapter(
         DynamicRangeAttribute attribute,
-        IStringLocalizer stringLocalizer)
+        IStringLocalizer? stringLocalizer)
         : base(attribute, stringLocalizer)
     {
-        _min = Convert.ToString(Attribute.Minimum, CultureInfo.InvariantCulture);
-        _max = Convert.ToString(Attribute.Maximum, CultureInfo.InvariantCulture);
+        _min = Convert.ToString(Attribute.Minimum, CultureInfo.InvariantCulture)!;
+        _max = Convert.ToString(Attribute.Maximum, CultureInfo.InvariantCulture)!;
     }
 
     public override void AddValidation(ClientModelValidationContext context)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicStringLengthAttributeAdapter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicStringLengthAttributeAdapter.cs
index 36aa4b91f9..fbdeead63f 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicStringLengthAttributeAdapter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/DataAnnotations/DynamicStringLengthAttributeAdapter.cs
@@ -14,7 +14,7 @@ public class DynamicStringLengthAttributeAdapter : AttributeAdapterBase<DynamicS
 
     public DynamicStringLengthAttributeAdapter(
         DynamicStringLengthAttribute attribute,
-        IStringLocalizer stringLocalizer)
+        IStringLocalizer? stringLocalizer)
         : base(attribute, stringLocalizer)
     {
         _max = Attribute.MaximumLength.ToString(CultureInfo.InvariantCulture);
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ExceptionHandling/AbpExceptionFilter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ExceptionHandling/AbpExceptionFilter.cs
index 05a3f52c72..61e37104ee 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ExceptionHandling/AbpExceptionFilter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ExceptionHandling/AbpExceptionFilter.cs
@@ -77,7 +77,7 @@ public class AbpExceptionFilter : IAsyncExceptionFilter, ITransientDependency
             context.Result = new ObjectResult(new RemoteServiceErrorResponse(remoteServiceErrorInfo));
         }
 
-        context.Exception = null; //Handled!
+        context.Exception = null!; //Handled!
     }
 
     protected virtual void LogException(ExceptionContext context, out RemoteServiceErrorInfo remoteServiceErrorInfo)
@@ -94,7 +94,7 @@ public class AbpExceptionFilter : IAsyncExceptionFilter, ITransientDependency
         remoteServiceErrorInfoBuilder.AppendLine($"---------- {nameof(RemoteServiceErrorInfo)} ----------");
         remoteServiceErrorInfoBuilder.AppendLine(context.GetRequiredService<IJsonSerializer>().Serialize(remoteServiceErrorInfo, indented: true));
 
-        var logger = context.GetService<ILogger<AbpExceptionFilter>>(NullLogger<AbpExceptionFilter>.Instance);
+        var logger = context.GetService<ILogger<AbpExceptionFilter>>(NullLogger<AbpExceptionFilter>.Instance)!;
         var logLevel = context.Exception.GetLogLevel();
         logger.LogWithLevel(logLevel, remoteServiceErrorInfoBuilder.ToString());
         logger.LogException(context.Exception, logLevel);
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ExceptionHandling/AbpExceptionPageFilter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ExceptionHandling/AbpExceptionPageFilter.cs
index f595cd16ad..9db528d620 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ExceptionHandling/AbpExceptionPageFilter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ExceptionHandling/AbpExceptionPageFilter.cs
@@ -47,7 +47,7 @@ public class AbpExceptionPageFilter : IAsyncPageFilter, ITransientDependency
         //TODO: Create DontWrap attribute to control wrapping..?
 
         if (context.ActionDescriptor.IsPageAction() &&
-            ActionResultHelper.IsObjectResult(context.HandlerMethod.MethodInfo.ReturnType, typeof(void)))
+            ActionResultHelper.IsObjectResult(context.HandlerMethod!.MethodInfo.ReturnType, typeof(void)))
         {
             return true;
         }
@@ -71,24 +71,24 @@ public class AbpExceptionPageFilter : IAsyncPageFilter, ITransientDependency
 
         var exceptionHandlingOptions = context.GetRequiredService<IOptions<AbpExceptionHandlingOptions>>().Value;
         var exceptionToErrorInfoConverter = context.GetRequiredService<IExceptionToErrorInfoConverter>();
-        var remoteServiceErrorInfo = exceptionToErrorInfoConverter.Convert(context.Exception, options =>
+        var remoteServiceErrorInfo = exceptionToErrorInfoConverter.Convert(context.Exception!, options =>
        {
            options.SendExceptionsDetailsToClients = exceptionHandlingOptions.SendExceptionsDetailsToClients;
            options.SendStackTraceToClients = exceptionHandlingOptions.SendStackTraceToClients;
        });
 
-        var logLevel = context.Exception.GetLogLevel();
+        var logLevel = context.Exception!.GetLogLevel();
 
         var remoteServiceErrorInfoBuilder = new StringBuilder();
         remoteServiceErrorInfoBuilder.AppendLine($"---------- {nameof(RemoteServiceErrorInfo)} ----------");
         remoteServiceErrorInfoBuilder.AppendLine(context.GetRequiredService<IJsonSerializer>().Serialize(remoteServiceErrorInfo, indented: true));
 
-        var logger = context.GetService<ILogger<AbpExceptionFilter>>(NullLogger<AbpExceptionFilter>.Instance);
+        var logger = context.GetService<ILogger<AbpExceptionFilter>>(NullLogger<AbpExceptionFilter>.Instance)!;
         logger.LogWithLevel(logLevel, remoteServiceErrorInfoBuilder.ToString());
 
-        logger.LogException(context.Exception, logLevel);
+        logger.LogException(context.Exception!, logLevel);
 
-        await context.GetRequiredService<IExceptionNotifier>().NotifyAsync(new ExceptionNotificationContext(context.Exception));
+        await context.GetRequiredService<IExceptionNotifier>().NotifyAsync(new ExceptionNotificationContext(context.Exception!));
 
         if (context.Exception is AbpAuthorizationException)
         {
@@ -100,7 +100,7 @@ public class AbpExceptionPageFilter : IAsyncPageFilter, ITransientDependency
             context.HttpContext.Response.Headers.Add(AbpHttpConsts.AbpErrorFormat, "true");
             context.HttpContext.Response.StatusCode = (int)context
                 .GetRequiredService<IHttpExceptionStatusCodeFinder>()
-                .GetStatusCode(context.HttpContext, context.Exception);
+                .GetStatusCode(context.HttpContext, context.Exception!);
 
             context.Result = new ObjectResult(new RemoteServiceErrorResponse(remoteServiceErrorInfo));
         }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/GlobalFeatures/GlobalFeatureActionFilter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/GlobalFeatures/GlobalFeatureActionFilter.cs
index 6daff20ff8..7b7ccf7db7 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/GlobalFeatures/GlobalFeatureActionFilter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/GlobalFeatures/GlobalFeatureActionFilter.cs
@@ -23,7 +23,7 @@ public class GlobalFeatureActionFilter : IAsyncActionFilter, ITransientDependenc
 
         if (!GlobalFeatureHelper.IsGlobalFeatureEnabled(context.Controller.GetType(), out var attribute))
         {
-            var logger = context.GetService<ILogger<GlobalFeatureActionFilter>>(NullLogger<GlobalFeatureActionFilter>.Instance);
+            var logger = context.GetService<ILogger<GlobalFeatureActionFilter>>(NullLogger<GlobalFeatureActionFilter>.Instance)!;
             logger.LogWarning($"The '{context.Controller.GetType().FullName}' controller needs to enable '{attribute.Name}' feature.");
             context.Result = new NotFoundResult();
             return;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/GlobalFeatures/GlobalFeaturePageFilter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/GlobalFeatures/GlobalFeaturePageFilter.cs
index d61024e919..c557b6c5bd 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/GlobalFeatures/GlobalFeaturePageFilter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/GlobalFeatures/GlobalFeaturePageFilter.cs
@@ -28,7 +28,7 @@ public class GlobalFeaturePageFilter : IAsyncPageFilter, ITransientDependency
 
         if (!GlobalFeatureHelper.IsGlobalFeatureEnabled(context.HandlerInstance.GetType(), out var attribute))
         {
-            var logger = context.GetService<ILogger<GlobalFeatureActionFilter>>(NullLogger<GlobalFeatureActionFilter>.Instance);
+            var logger = context.GetService<ILogger<GlobalFeatureActionFilter>>(NullLogger<GlobalFeatureActionFilter>.Instance)!;
             logger.LogWarning($"The '{context.HandlerInstance.GetType().FullName}' page needs to enable '{attribute.Name}' feature.");
             context.Result = new NotFoundResult();
             return;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Localization/AbpMvcAttributeValidationResultProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Localization/AbpMvcAttributeValidationResultProvider.cs
index 690c82c9b1..34aeb2c44c 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Localization/AbpMvcAttributeValidationResultProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Localization/AbpMvcAttributeValidationResultProvider.cs
@@ -22,7 +22,7 @@ public class AbpMvcAttributeValidationResultProvider : DefaultAttributeValidatio
         _stringLocalizerFactory = stringLocalizerFactory;
     }
 
-    public override ValidationResult GetOrDefault(ValidationAttribute validationAttribute, object validatingObject, ValidationContext validationContext)
+    public override ValidationResult? GetOrDefault(ValidationAttribute validationAttribute, object? validatingObject, ValidationContext validationContext)
     {
         var resourceSource = _abpMvcDataAnnotationsLocalizationOptions.AssemblyResources.GetOrDefault(validationContext.ObjectType.Assembly);
         if (resourceSource == null)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpDateTimeModelBinderProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpDateTimeModelBinderProvider.cs
index 0f122e70f5..a4c3ee2288 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpDateTimeModelBinderProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpDateTimeModelBinderProvider.cs
@@ -12,7 +12,7 @@ namespace Volo.Abp.AspNetCore.Mvc.ModelBinding;
 
 public class AbpDateTimeModelBinderProvider : IModelBinderProvider
 {
-    public IModelBinder GetBinder(ModelBinderProviderContext context)
+    public IModelBinder? GetBinder(ModelBinderProviderContext context)
     {
         var modelType = context.Metadata.UnderlyingOrModelType;
         if (modelType == typeof(DateTime))
@@ -31,7 +31,7 @@ public class AbpDateTimeModelBinderProvider : IModelBinderProvider
                     context.Metadata.ContainerType.IsDefined(typeof(DisableDateTimeNormalizationAttribute), true);
 
                 var dateNormalizationDisabledForProperty = context.Metadata.ContainerType
-                    .GetProperty(context.Metadata.PropertyName)
+                    .GetProperty(context.Metadata.PropertyName!)
                     ?.IsDefined(typeof(DisableDateTimeNormalizationAttribute), true);
 
                 if (!dateNormalizationDisabledForClass &&
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpExtraPropertiesDictionaryModelBinderProvider.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpExtraPropertiesDictionaryModelBinderProvider.cs
index 4412194ad7..d0c3160092 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpExtraPropertiesDictionaryModelBinderProvider.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpExtraPropertiesDictionaryModelBinderProvider.cs
@@ -11,7 +11,7 @@ namespace Volo.Abp.AspNetCore.Mvc.ModelBinding;
 
 public class AbpExtraPropertiesDictionaryModelBinderProvider : IModelBinderProvider
 {
-    public IModelBinder GetBinder(ModelBinderProviderContext context)
+    public IModelBinder? GetBinder(ModelBinderProviderContext context)
     {
         if (context == null)
         {
@@ -41,6 +41,6 @@ public class AbpExtraPropertiesDictionaryModelBinderProvider : IModelBinderProvi
             valueBinder,
             loggerFactory,
             true /* allowValidatingTopLevelNodes */,
-            mvcOptions);
+            mvcOptions)!;
     }
 }
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpExtraPropertyModelBinder.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpExtraPropertyModelBinder.cs
index 3ff9b0f760..deebcf4a39 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpExtraPropertyModelBinder.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/AbpExtraPropertyModelBinder.cs
@@ -35,7 +35,7 @@ public class AbpExtraPropertyModelBinder : IModelBinder
         return Task.CompletedTask;
     }
 
-    protected virtual object ConvertStringToPropertyType(ModelBindingContext bindingContext, string value)
+    protected virtual object? ConvertStringToPropertyType(ModelBindingContext bindingContext, string? value)
     {
         if (bindingContext.ModelMetadata.ConvertEmptyStringToNull && string.IsNullOrWhiteSpace(value))
         {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/ExtraPropertyBindingHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/ExtraPropertyBindingHelper.cs
index 646cbf0c4b..46aef196cc 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/ExtraPropertyBindingHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ModelBinding/ExtraPropertyBindingHelper.cs
@@ -8,7 +8,7 @@ public static class ExtraPropertyBindingHelper
     /// <paramref name="expression"/> is a string like "UserInfo.ExtraProperties[SocialSecurityNumber]"
     /// This method returns "SocialSecurityNumber" for this example. */
     /// </summary>
-    public static string ExtractExtraPropertyName(string expression)
+    public static string? ExtractExtraPropertyName(string expression)
     {
         var index = expression.IndexOf("ExtraProperties[", StringComparison.Ordinal);
         if (index < 0)
@@ -23,7 +23,7 @@ public static class ExtraPropertyBindingHelper
     /// <paramref name="expression"/> is a string like "UserInfo.ExtraProperties[SocialSecurityNumber]"
     /// This method returns "UserInfo" for this example.
     /// </summary>
-    public static string ExtractContainerName(string expression)
+    public static string? ExtractContainerName(string expression)
     {
         var index = expression.IndexOf("ExtraProperties[", StringComparison.Ordinal);
         if (index < 0)
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ProxyScripting/ServiceProxyGenerationModel.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ProxyScripting/ServiceProxyGenerationModel.cs
index 3501882e3a..b912d3905a 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ProxyScripting/ServiceProxyGenerationModel.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/ProxyScripting/ServiceProxyGenerationModel.cs
@@ -7,15 +7,15 @@ namespace Volo.Abp.AspNetCore.Mvc.ProxyScripting;
 
 public class ServiceProxyGenerationModel
 {
-    public string Type { get; set; }
+    public string? Type { get; set; }
 
     public bool UseCache { get; set; }
 
-    public string Modules { get; set; }
+    public string? Modules { get; set; }
 
-    public string Controllers { get; set; }
+    public string? Controllers { get; set; }
 
-    public string Actions { get; set; }
+    public string? Actions { get; set; }
 
     public ServiceProxyGenerationModel()
     {
@@ -36,17 +36,17 @@ public class ServiceProxyGenerationModel
 
         if (!Modules.IsNullOrEmpty())
         {
-            options.Modules = Modules.Split('|').Select(m => m.Trim()).ToArray();
+            options.Modules = Modules!.Split('|').Select(m => m.Trim()).ToArray();
         }
 
         if (!Controllers.IsNullOrEmpty())
         {
-            options.Controllers = Controllers.Split('|').Select(m => m.Trim()).ToArray();
+            options.Controllers = Controllers!.Split('|').Select(m => m.Trim()).ToArray();
         }
 
         if (!Actions.IsNullOrEmpty())
         {
-            options.Actions = Actions.Split('|').Select(m => m.Trim()).ToArray();
+            options.Actions = Actions!.Split('|').Select(m => m.Trim()).ToArray();
         }
 
         return options;
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Uow/AbpUowActionFilter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Uow/AbpUowActionFilter.cs
index 8f6cc2abf8..14032b52d5 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Uow/AbpUowActionFilter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Uow/AbpUowActionFilter.cs
@@ -67,7 +67,7 @@ public class AbpUowActionFilter : IAsyncActionFilter, ITransientDependency
         }
     }
 
-    private AbpUnitOfWorkOptions CreateOptions(ActionExecutingContext context, UnitOfWorkAttribute unitOfWorkAttribute)
+    private AbpUnitOfWorkOptions CreateOptions(ActionExecutingContext context, UnitOfWorkAttribute? unitOfWorkAttribute)
     {
         var options = new AbpUnitOfWorkOptions();
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Uow/AbpUowPageFilter.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Uow/AbpUowPageFilter.cs
index 57e1df8558..7cfc1f0492 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Uow/AbpUowPageFilter.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Uow/AbpUowPageFilter.cs
@@ -73,7 +73,7 @@ public class AbpUowPageFilter : IAsyncPageFilter, ITransientDependency
         }
     }
 
-    private AbpUnitOfWorkOptions CreateOptions(PageHandlerExecutingContext context, UnitOfWorkAttribute unitOfWorkAttribute)
+    private AbpUnitOfWorkOptions CreateOptions(PageHandlerExecutingContext context, UnitOfWorkAttribute? unitOfWorkAttribute)
     {
         var options = new AbpUnitOfWorkOptions();
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Utils/ArrayMatcher.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Utils/ArrayMatcher.cs
index 10198264c2..c785964f1f 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Utils/ArrayMatcher.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Utils/ArrayMatcher.cs
@@ -33,7 +33,7 @@ internal static class ArrayMatcher
             }
 
             var resultItem = EqualityComparer<T>.Default.Equals(parentItem, default) ? sourceItem : parentItem;
-            result.Add(resultItem);
+            result.Add(resultItem!);
         }
 
         return result.ToArray();
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Validation/ValidationAttributeHelper.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Validation/ValidationAttributeHelper.cs
index ccec4e0c01..505c07a3e1 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Validation/ValidationAttributeHelper.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Validation/ValidationAttributeHelper.cs
@@ -6,10 +6,10 @@ namespace Volo.Abp.AspNetCore.Mvc.Validation;
 public static class ValidationAttributeHelper
 {
     private static readonly PropertyInfo ValidationAttributeErrorMessageStringProperty = typeof(ValidationAttribute)
-        .GetProperty("ErrorMessageString", BindingFlags.Instance | BindingFlags.NonPublic);
+        .GetProperty("ErrorMessageString", BindingFlags.Instance | BindingFlags.NonPublic)!;
 
     private static readonly PropertyInfo ValidationAttributeCustomErrorMessageSetProperty = typeof(ValidationAttribute)
-        .GetProperty("CustomErrorMessageSet", BindingFlags.Instance | BindingFlags.NonPublic);
+        .GetProperty("CustomErrorMessageSet", BindingFlags.Instance | BindingFlags.NonPublic)!;
 
     public static void SetDefaultErrorMessage(ValidationAttribute validationAttribute)
     {
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Versioning/HttpContextRequestedApiVersion.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Versioning/HttpContextRequestedApiVersion.cs
index 09db4c3ce2..b634799fb1 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Versioning/HttpContextRequestedApiVersion.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Versioning/HttpContextRequestedApiVersion.cs
@@ -6,7 +6,7 @@ namespace Volo.Abp.AspNetCore.Mvc.Versioning;
 
 public class HttpContextRequestedApiVersion : IRequestedApiVersion
 {
-    public string Current => _httpContextAccessor.HttpContext?.GetRequestedApiVersion()?.ToString();
+    public string? Current => _httpContextAccessor.HttpContext?.GetRequestedApiVersion()?.ToString();
 
     private readonly IHttpContextAccessor _httpContextAccessor;
 
diff --git a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/ObjectExtending/ObjectExtensionPropertyInfoAspNetCoreMvcExtensions.cs b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/ObjectExtending/ObjectExtensionPropertyInfoAspNetCoreMvcExtensions.cs
index b1c61d95bb..b154628a6a 100644
--- a/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/ObjectExtending/ObjectExtensionPropertyInfoAspNetCoreMvcExtensions.cs
+++ b/framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/ObjectExtending/ObjectExtensionPropertyInfoAspNetCoreMvcExtensions.cs
@@ -34,7 +34,7 @@ public static class ObjectExtensionPropertyInfoAspNetCoreMvcExtensions
             .FirstOrDefault()?.DataType;
     }
 
-    public static string GetDataFormatStringOrNull(this IBasicObjectExtensionPropertyInfo property)
+    public static string? GetDataFormatStringOrNull(this IBasicObjectExtensionPropertyInfo property)
     {
         return property
             .Attributes
diff --git a/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/CacheNameAttribute.cs b/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/CacheNameAttribute.cs
index c49225acbf..53a7919ebb 100644
--- a/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/CacheNameAttribute.cs
+++ b/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/CacheNameAttribute.cs
@@ -33,6 +33,6 @@ public class CacheNameAttribute : Attribute
             return cacheNameAttribute.Name;
         }
 
-        return cacheItemType.FullName.RemovePostFix("CacheItem")!;
+        return cacheItemType.FullName!.RemovePostFix("CacheItem")!;
     }
 }
diff --git a/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/DistributedCache.cs b/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/DistributedCache.cs
index 03e42b5d92..ae571cb5f9 100644
--- a/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/DistributedCache.cs
+++ b/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/DistributedCache.cs
@@ -861,8 +861,7 @@ public class DistributedCache<TCacheItem, TCacheKey> : IDistributedCache<TCacheI
                 uowCache.Add(key, new UnitOfWorkCacheItem<TCacheItem>(value));
             }
 
-            // ReSharper disable once PossibleNullReferenceException
-            UnitOfWorkManager.Current.OnCompleted(() =>
+            UnitOfWorkManager.Current?.OnCompleted(() =>
             {
                 SetRealCache();
                 return Task.CompletedTask;
@@ -928,8 +927,7 @@ public class DistributedCache<TCacheItem, TCacheKey> : IDistributedCache<TCacheI
                 uowCache.Add(key, new UnitOfWorkCacheItem<TCacheItem>(value));
             }
 
-            // ReSharper disable once PossibleNullReferenceException
-            UnitOfWorkManager.Current.OnCompleted(SetRealCache);
+            UnitOfWorkManager.Current?.OnCompleted(SetRealCache);
         }
         else
         {
@@ -997,8 +995,7 @@ public class DistributedCache<TCacheItem, TCacheKey> : IDistributedCache<TCacheI
                 }
             }
 
-            // ReSharper disable once PossibleNullReferenceException
-            UnitOfWorkManager.Current.OnCompleted(() =>
+            UnitOfWorkManager.Current?.OnCompleted(() =>
             {
                 SetRealCache();
                 return Task.CompletedTask;
@@ -1106,8 +1103,7 @@ public class DistributedCache<TCacheItem, TCacheKey> : IDistributedCache<TCacheI
                 }
             }
 
-            // ReSharper disable once PossibleNullReferenceException
-            UnitOfWorkManager.Current.OnCompleted(SetRealCache);
+            UnitOfWorkManager.Current?.OnCompleted(SetRealCache);
         }
         else
         {
@@ -1311,8 +1307,7 @@ public class DistributedCache<TCacheItem, TCacheKey> : IDistributedCache<TCacheI
                 uowCache[key].RemoveValue();
             }
 
-            // ReSharper disable once PossibleNullReferenceException
-            UnitOfWorkManager.Current.OnCompleted(() =>
+            UnitOfWorkManager.Current?.OnCompleted(() =>
             {
                 RemoveRealCache();
                 return Task.CompletedTask;
@@ -1366,8 +1361,7 @@ public class DistributedCache<TCacheItem, TCacheKey> : IDistributedCache<TCacheI
                 uowCache[key].RemoveValue();
             }
 
-            // ReSharper disable once PossibleNullReferenceException
-            UnitOfWorkManager.Current.OnCompleted(RemoveRealCache);
+            UnitOfWorkManager.Current?.OnCompleted(RemoveRealCache);
         }
         else
         {
@@ -1418,8 +1412,7 @@ public class DistributedCache<TCacheItem, TCacheKey> : IDistributedCache<TCacheI
                     }
                 }
 
-                // ReSharper disable once PossibleNullReferenceException
-                UnitOfWorkManager.Current.OnCompleted(() =>
+                UnitOfWorkManager.Current?.OnCompleted(() =>
                 {
                     RemoveRealCache();
                     return Task.CompletedTask;
@@ -1482,8 +1475,7 @@ public class DistributedCache<TCacheItem, TCacheKey> : IDistributedCache<TCacheI
                     }
                 }
 
-                // ReSharper disable once PossibleNullReferenceException
-                UnitOfWorkManager.Current.OnCompleted(RemoveRealCache);
+                UnitOfWorkManager.Current?.OnCompleted(RemoveRealCache);
             }
             else
             {
diff --git a/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/Utf8JsonDistributedCacheSerializer.cs b/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/Utf8JsonDistributedCacheSerializer.cs
index a83767d45d..baab3b7a0c 100644
--- a/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/Utf8JsonDistributedCacheSerializer.cs
+++ b/framework/src/Volo.Abp.Caching/Volo/Abp/Caching/Utf8JsonDistributedCacheSerializer.cs
@@ -15,7 +15,7 @@ public class Utf8JsonDistributedCacheSerializer : IDistributedCacheSerializer, I
 
     public byte[] Serialize<T>(T obj)
     {
-        return Encoding.UTF8.GetBytes(JsonSerializer.Serialize(obj));
+        return Encoding.UTF8.GetBytes(JsonSerializer.Serialize(obj!));
     }
 
     public T Deserialize<T>(byte[] bytes)