diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/Data/MyProjectNameDbMigrationService.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/Data/MyProjectNameDbMigrationService.cs
index 1d598a1ce9..54a179ea61 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/Data/MyProjectNameDbMigrationService.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/Data/MyProjectNameDbMigrationService.cs
@@ -70,13 +70,13 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         Logger.LogInformation("You can safely end this process...");
     }
 
-    private async Task MigrateDatabaseSchemaAsync(Tenant tenant = null)
+    private async Task MigrateDatabaseSchemaAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Migrating schema for {(tenant == null ? "host" : tenant.Name + " tenant")} database...");
         await _dbSchemaMigrator.MigrateAsync();
     }
 
-    private async Task SeedDataAsync(Tenant tenant = null)
+    private async Task SeedDataAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Executing {(tenant == null ? "host" : tenant.Name + " tenant")} database seed...");
 
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/MyCompanyName.MyProjectName.Blazor.Server.Mongo.csproj b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/MyCompanyName.MyProjectName.Blazor.Server.Mongo.csproj
index 0983f7740c..7f4f101afa 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/MyCompanyName.MyProjectName.Blazor.Server.Mongo.csproj
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/MyCompanyName.MyProjectName.Blazor.Server.Mongo.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <GenerateEmbeddedFilesManifest>true</GenerateEmbeddedFilesManifest>
   </PropertyGroup>
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/MyProjectNameModule.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/MyProjectNameModule.cs
index f234a8b833..e088b4a84f 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/MyProjectNameModule.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server.Mongo/MyProjectNameModule.cs
@@ -164,7 +164,7 @@ public class MyProjectNameModule : AbpModule
         Configure<AppUrlOptions>(options =>
         {
             options.Applications["MVC"].RootUrl = configuration["App:SelfUrl"];
-            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"].Split(','));
+            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"]?.Split(',') ?? Array.Empty<string>());
         });
     }
 
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/Data/MyProjectNameDbMigrationService.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/Data/MyProjectNameDbMigrationService.cs
index eeffd14d64..352c55ef26 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/Data/MyProjectNameDbMigrationService.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/Data/MyProjectNameDbMigrationService.cs
@@ -79,13 +79,13 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         Logger.LogInformation("You can safely end this process...");
     }
 
-    private async Task MigrateDatabaseSchemaAsync(Tenant tenant = null)
+    private async Task MigrateDatabaseSchemaAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Migrating schema for {(tenant == null ? "host" : tenant.Name + " tenant")} database...");
         await _dbSchemaMigrator.MigrateAsync();
     }
 
-    private async Task SeedDataAsync(Tenant tenant = null)
+    private async Task SeedDataAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Executing {(tenant == null ? "host" : tenant.Name + " tenant")} database seed...");
 
@@ -184,15 +184,15 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         return Path.Combine(slnDirectoryPath, "MyCompanyName.MyProjectName.Blazor.Server");
     }
 
-    private string GetSolutionDirectoryPath()
+    private string? GetSolutionDirectoryPath()
     {
         var currentDirectory = new DirectoryInfo(Directory.GetCurrentDirectory());
 
-        while (Directory.GetParent(currentDirectory.FullName) != null)
+        while (currentDirectory != null && Directory.GetParent(currentDirectory.FullName) != null)
         {
             currentDirectory = Directory.GetParent(currentDirectory.FullName);
 
-            if (Directory.GetFiles(currentDirectory.FullName).FirstOrDefault(f => f.EndsWith(".sln")) != null)
+            if (currentDirectory != null && Directory.GetFiles(currentDirectory.FullName).FirstOrDefault(f => f.EndsWith(".sln")) != null)
             {
                 return currentDirectory.FullName;
             }
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj
index 8573e93e48..6161a2f87d 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <GenerateEmbeddedFilesManifest>true</GenerateEmbeddedFilesManifest>
   </PropertyGroup>
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/MyProjectNameModule.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/MyProjectNameModule.cs
index 6defe2cc2c..b0953ae2eb 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/MyProjectNameModule.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Blazor.Server/MyProjectNameModule.cs
@@ -166,7 +166,7 @@ public class MyProjectNameModule : AbpModule
         Configure<AppUrlOptions>(options =>
         {
             options.Applications["MVC"].RootUrl = configuration["App:SelfUrl"];
-            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"].Split(','));
+            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"]?.Split(',') ?? Array.Empty<string>());
         });
     }
 
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/Data/MyProjectNameDbMigrationService.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/Data/MyProjectNameDbMigrationService.cs
index 1d598a1ce9..54a179ea61 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/Data/MyProjectNameDbMigrationService.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/Data/MyProjectNameDbMigrationService.cs
@@ -70,13 +70,13 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         Logger.LogInformation("You can safely end this process...");
     }
 
-    private async Task MigrateDatabaseSchemaAsync(Tenant tenant = null)
+    private async Task MigrateDatabaseSchemaAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Migrating schema for {(tenant == null ? "host" : tenant.Name + " tenant")} database...");
         await _dbSchemaMigrator.MigrateAsync();
     }
 
-    private async Task SeedDataAsync(Tenant tenant = null)
+    private async Task SeedDataAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Executing {(tenant == null ? "host" : tenant.Name + " tenant")} database seed...");
 
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/Data/OpenIddictDataSeedContributor.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/Data/OpenIddictDataSeedContributor.cs
index 429a83d562..8807969649 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/Data/OpenIddictDataSeedContributor.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/Data/OpenIddictDataSeedContributor.cs
@@ -78,7 +78,7 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         {
             var webClientRootUrl = configurationSection["MyProjectName_App:RootUrl"]?.TrimEnd('/');
             await CreateApplicationAsync(
-                name: consoleAndAngularClientId,
+                name: consoleAndAngularClientId!,
                 type: OpenIddictConstants.ClientTypes.Public,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Console Test / Angular Application",
@@ -100,10 +100,10 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         var swaggerClientId = configurationSection["MyProjectName_Swagger:ClientId"];
         if (!swaggerClientId.IsNullOrWhiteSpace())
         {
-            var swaggerRootUrl = configurationSection["MyProjectName_Swagger:RootUrl"].TrimEnd('/');
+            var swaggerRootUrl = configurationSection["MyProjectName_Swagger:RootUrl"]?.TrimEnd('/');
 
             await CreateApplicationAsync(
-                name: swaggerClientId,
+                name: swaggerClientId!,
                 type: OpenIddictConstants.ClientTypes.Public,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Swagger Application",
@@ -123,12 +123,12 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         [NotNull] string type,
         [NotNull] string consentType,
         string displayName,
-        string secret,
+        string? secret,
         List<string> grantTypes,
         List<string> scopes,
-        string redirectUri = null,
-        string postLogoutRedirectUri = null,
-        List<string> permissions = null)
+        string? redirectUri = null,
+        string? postLogoutRedirectUri = null,
+        List<string>? permissions = null)
     {
         if (!string.IsNullOrEmpty(secret) && string.Equals(type, OpenIddictConstants.ClientTypes.Public, StringComparison.OrdinalIgnoreCase))
         {
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/MyCompanyName.MyProjectName.Host.Mongo.csproj b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/MyCompanyName.MyProjectName.Host.Mongo.csproj
index 60712105a2..62eda99090 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/MyCompanyName.MyProjectName.Host.Mongo.csproj
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/MyCompanyName.MyProjectName.Host.Mongo.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <GenerateEmbeddedFilesManifest>true</GenerateEmbeddedFilesManifest>
   </PropertyGroup>
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/MyProjectNameModule.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/MyProjectNameModule.cs
index 45e5006b8a..aa072a238e 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/MyProjectNameModule.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host.Mongo/MyProjectNameModule.cs
@@ -171,7 +171,7 @@ public class MyProjectNameModule : AbpModule
         Configure<AppUrlOptions>(options =>
         {
             options.Applications["MVC"].RootUrl = configuration["App:SelfUrl"];
-            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"].Split(','));
+            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"]?.Split(',') ?? Array.Empty<string>());
 
             options.Applications["Angular"].RootUrl = configuration["App:ClientUrl"];
             options.Applications["Angular"].Urls[AccountUrlNames.PasswordReset] = "account/reset-password";
@@ -275,10 +275,10 @@ public class MyProjectNameModule : AbpModule
             {
                 builder
                     .WithOrigins(
-                        configuration["App:CorsOrigins"]
+                        configuration["App:CorsOrigins"]?
                             .Split(",", StringSplitOptions.RemoveEmptyEntries)
                             .Select(o => o.RemovePostFix("/"))
-                            .ToArray()
+                            .ToArray() ?? Array.Empty<string>()
                     )
                     .WithAbpExposedHeaders()
                     .SetIsOriginAllowedToAllowWildcardSubdomains()
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/Data/MyProjectNameDbMigrationService.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/Data/MyProjectNameDbMigrationService.cs
index b0b929dcc9..83d4f3dcbb 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/Data/MyProjectNameDbMigrationService.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/Data/MyProjectNameDbMigrationService.cs
@@ -79,13 +79,13 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         Logger.LogInformation("You can safely end this process...");
     }
 
-    private async Task MigrateDatabaseSchemaAsync(Tenant tenant = null)
+    private async Task MigrateDatabaseSchemaAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Migrating schema for {(tenant == null ? "host" : tenant.Name + " tenant")} database...");
         await _dbSchemaMigrator.MigrateAsync();
     }
 
-    private async Task SeedDataAsync(Tenant tenant = null)
+    private async Task SeedDataAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Executing {(tenant == null ? "host" : tenant.Name + " tenant")} database seed...");
 
@@ -184,15 +184,15 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         return Path.Combine(slnDirectoryPath, "MyCompanyName.MyProjectName.Host");
     }
 
-    private string GetSolutionDirectoryPath()
+    private string? GetSolutionDirectoryPath()
     {
         var currentDirectory = new DirectoryInfo(Directory.GetCurrentDirectory());
 
-        while (Directory.GetParent(currentDirectory.FullName) != null)
+        while (currentDirectory != null && Directory.GetParent(currentDirectory.FullName) != null)
         {
             currentDirectory = Directory.GetParent(currentDirectory.FullName);
 
-            if (Directory.GetFiles(currentDirectory.FullName).FirstOrDefault(f => f.EndsWith(".sln")) != null)
+            if (currentDirectory != null && Directory.GetFiles(currentDirectory.FullName).FirstOrDefault(f => f.EndsWith(".sln")) != null)
             {
                 return currentDirectory.FullName;
             }
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/Data/OpenIddictDataSeedContributor.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/Data/OpenIddictDataSeedContributor.cs
index 429a83d562..8807969649 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/Data/OpenIddictDataSeedContributor.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/Data/OpenIddictDataSeedContributor.cs
@@ -78,7 +78,7 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         {
             var webClientRootUrl = configurationSection["MyProjectName_App:RootUrl"]?.TrimEnd('/');
             await CreateApplicationAsync(
-                name: consoleAndAngularClientId,
+                name: consoleAndAngularClientId!,
                 type: OpenIddictConstants.ClientTypes.Public,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Console Test / Angular Application",
@@ -100,10 +100,10 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         var swaggerClientId = configurationSection["MyProjectName_Swagger:ClientId"];
         if (!swaggerClientId.IsNullOrWhiteSpace())
         {
-            var swaggerRootUrl = configurationSection["MyProjectName_Swagger:RootUrl"].TrimEnd('/');
+            var swaggerRootUrl = configurationSection["MyProjectName_Swagger:RootUrl"]?.TrimEnd('/');
 
             await CreateApplicationAsync(
-                name: swaggerClientId,
+                name: swaggerClientId!,
                 type: OpenIddictConstants.ClientTypes.Public,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Swagger Application",
@@ -123,12 +123,12 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         [NotNull] string type,
         [NotNull] string consentType,
         string displayName,
-        string secret,
+        string? secret,
         List<string> grantTypes,
         List<string> scopes,
-        string redirectUri = null,
-        string postLogoutRedirectUri = null,
-        List<string> permissions = null)
+        string? redirectUri = null,
+        string? postLogoutRedirectUri = null,
+        List<string>? permissions = null)
     {
         if (!string.IsNullOrEmpty(secret) && string.Equals(type, OpenIddictConstants.ClientTypes.Public, StringComparison.OrdinalIgnoreCase))
         {
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/MyCompanyName.MyProjectName.Host.csproj b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/MyCompanyName.MyProjectName.Host.csproj
index afb804eae6..68cdc93feb 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/MyCompanyName.MyProjectName.Host.csproj
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/MyCompanyName.MyProjectName.Host.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <GenerateEmbeddedFilesManifest>true</GenerateEmbeddedFilesManifest>
   </PropertyGroup>
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/MyProjectNameModule.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/MyProjectNameModule.cs
index 16ef3cf47b..bbc6b36262 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/MyProjectNameModule.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Host/MyProjectNameModule.cs
@@ -174,7 +174,7 @@ public class MyProjectNameModule : AbpModule
         Configure<AppUrlOptions>(options =>
         {
             options.Applications["MVC"].RootUrl = configuration["App:SelfUrl"];
-            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"].Split(','));
+            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"]?.Split(',') ?? Array.Empty<string>());
 
             options.Applications["Angular"].RootUrl = configuration["App:ClientUrl"];
             options.Applications["Angular"].Urls[AccountUrlNames.PasswordReset] = "account/reset-password";
@@ -278,10 +278,10 @@ public class MyProjectNameModule : AbpModule
             {
                 builder
                     .WithOrigins(
-                        configuration["App:CorsOrigins"]
+                        configuration["App:CorsOrigins"]?
                             .Split(",", StringSplitOptions.RemoveEmptyEntries)
                             .Select(o => o.RemovePostFix("/"))
-                            .ToArray()
+                            .ToArray() ?? Array.Empty<string>()
                     )
                     .WithAbpExposedHeaders()
                     .SetIsOriginAllowedToAllowWildcardSubdomains()
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc.Mongo/Data/MyProjectNameDbMigrationService.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc.Mongo/Data/MyProjectNameDbMigrationService.cs
index 1d598a1ce9..54a179ea61 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc.Mongo/Data/MyProjectNameDbMigrationService.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc.Mongo/Data/MyProjectNameDbMigrationService.cs
@@ -70,13 +70,13 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         Logger.LogInformation("You can safely end this process...");
     }
 
-    private async Task MigrateDatabaseSchemaAsync(Tenant tenant = null)
+    private async Task MigrateDatabaseSchemaAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Migrating schema for {(tenant == null ? "host" : tenant.Name + " tenant")} database...");
         await _dbSchemaMigrator.MigrateAsync();
     }
 
-    private async Task SeedDataAsync(Tenant tenant = null)
+    private async Task SeedDataAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Executing {(tenant == null ? "host" : tenant.Name + " tenant")} database seed...");
 
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc.Mongo/MyCompanyName.MyProjectName.Mvc.Mongo.csproj b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc.Mongo/MyCompanyName.MyProjectName.Mvc.Mongo.csproj
index 5f99ac74ae..a203e9e1cf 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc.Mongo/MyCompanyName.MyProjectName.Mvc.Mongo.csproj
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc.Mongo/MyCompanyName.MyProjectName.Mvc.Mongo.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <GenerateEmbeddedFilesManifest>true</GenerateEmbeddedFilesManifest>
   </PropertyGroup>
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc/Data/MyProjectNameDbMigrationService.cs b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc/Data/MyProjectNameDbMigrationService.cs
index 14db7d1e8d..d51d346284 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc/Data/MyProjectNameDbMigrationService.cs
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc/Data/MyProjectNameDbMigrationService.cs
@@ -79,13 +79,13 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         Logger.LogInformation("You can safely end this process...");
     }
 
-    private async Task MigrateDatabaseSchemaAsync(Tenant tenant = null)
+    private async Task MigrateDatabaseSchemaAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Migrating schema for {(tenant == null ? "host" : tenant.Name + " tenant")} database...");
         await _dbSchemaMigrator.MigrateAsync();
     }
 
-    private async Task SeedDataAsync(Tenant tenant = null)
+    private async Task SeedDataAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Executing {(tenant == null ? "host" : tenant.Name + " tenant")} database seed...");
 
@@ -184,15 +184,15 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         return Path.Combine(slnDirectoryPath, "MyCompanyName.MyProjectName.Mvc");
     }
 
-    private string GetSolutionDirectoryPath()
+    private string? GetSolutionDirectoryPath()
     {
         var currentDirectory = new DirectoryInfo(Directory.GetCurrentDirectory());
 
-        while (Directory.GetParent(currentDirectory.FullName) != null)
+        while (currentDirectory != null && Directory.GetParent(currentDirectory.FullName) != null)
         {
             currentDirectory = Directory.GetParent(currentDirectory.FullName);
 
-            if (Directory.GetFiles(currentDirectory.FullName).FirstOrDefault(f => f.EndsWith(".sln")) != null)
+            if (currentDirectory != null && Directory.GetFiles(currentDirectory.FullName).FirstOrDefault(f => f.EndsWith(".sln")) != null)
             {
                 return currentDirectory.FullName;
             }
diff --git a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc/MyCompanyName.MyProjectName.Mvc.csproj b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc/MyCompanyName.MyProjectName.Mvc.csproj
index c848ad3cf6..21cdc1b0db 100644
--- a/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc/MyCompanyName.MyProjectName.Mvc.csproj
+++ b/templates/app-nolayers/aspnet-core/MyCompanyName.MyProjectName.Mvc/MyCompanyName.MyProjectName.Mvc.csproj
@@ -2,6 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <GenerateEmbeddedFilesManifest>true</GenerateEmbeddedFilesManifest>
   </PropertyGroup>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Application.Contracts/MyCompanyName.MyProjectName.Application.Contracts.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Application.Contracts/MyCompanyName.MyProjectName.Application.Contracts.csproj
index 1e50cf8678..6029c23a7f 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Application.Contracts/MyCompanyName.MyProjectName.Application.Contracts.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Application.Contracts/MyCompanyName.MyProjectName.Application.Contracts.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Application/MyCompanyName.MyProjectName.Application.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Application/MyCompanyName.MyProjectName.Application.csproj
index 8037a452b4..a9c83b797b 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Application/MyCompanyName.MyProjectName.Application.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Application/MyCompanyName.MyProjectName.Application.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/MyCompanyName.MyProjectName.AuthServer.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/MyCompanyName.MyProjectName.AuthServer.csproj
index 21fb37e73e..70a55520a0 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/MyCompanyName.MyProjectName.AuthServer.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/MyCompanyName.MyProjectName.AuthServer.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/MyProjectNameAuthServerModule.cs b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/MyProjectNameAuthServerModule.cs
index fb963a81c7..c8f1c89424 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/MyProjectNameAuthServerModule.cs
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/MyProjectNameAuthServerModule.cs
@@ -114,7 +114,7 @@ public class MyProjectNameAuthServerModule : AbpModule
         Configure<AppUrlOptions>(options =>
         {
             options.Applications["MVC"].RootUrl = configuration["App:SelfUrl"];
-            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"].Split(','));
+            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"]?.Split(',') ?? Array.Empty<string>());
 
             options.Applications["Angular"].RootUrl = configuration["App:ClientUrl"];
             options.Applications["Angular"].Urls[AccountUrlNames.PasswordReset] = "account/reset-password";
@@ -150,10 +150,10 @@ public class MyProjectNameAuthServerModule : AbpModule
             {
                 builder
                     .WithOrigins(
-                        configuration["App:CorsOrigins"]
+                        configuration["App:CorsOrigins"]?
                             .Split(",", StringSplitOptions.RemoveEmptyEntries)
                             .Select(o => o.RemovePostFix("/"))
-                            .ToArray()
+                            .ToArray() ?? Array.Empty<string>()
                     )
                     .WithAbpExposedHeaders()
                     .SetIsOriginAllowedToAllowWildcardSubdomains()
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/Pages/Index.cshtml b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/Pages/Index.cshtml
index 48b2d8de02..e45ec1b8f1 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/Pages/Index.cshtml
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/Pages/Index.cshtml
@@ -19,10 +19,8 @@
 <div class="d-flex align-items-center" style="min-height: 100vh;">
     <div class="container">
         <abp-row>
-
             <div class="col mx-auto account-column">
                 <div class="account-brand p-4 text-center mb-1">
-
                     @if (!BrandingProvider.LogoUrl.IsNullOrEmpty())
                     {
                         <a class="navbar-brand" href="/" alt="@BrandingProvider.AppName"></a>
@@ -33,9 +31,7 @@
                     }
                 </div>
                 <abp-card>
-
                     <abp-card-body>
-
                         <div class="container">
                             <abp-row>
                                 <abp-column size="_9">
@@ -68,52 +64,51 @@
                                     <div class="ml-auto p-2 float-end">
                                         <abp-dropdown>
                                             <abp-dropdown-button text="@Model.CurrentLanguage" />
-                                            <abp-dropdown-menu>
-                                                @foreach (var language in Model.Languages)
-                                                {
-                                                    <abp-dropdown-item href="~/Abp/Languages/Switch?culture=@(language.CultureName)&uiCulture=@(language.UiCultureName)&returnUrl=@(System.Net.WebUtility.UrlEncode(Request.GetEncodedPathAndQuery()))">@language.DisplayName</abp-dropdown-item>
-                                                }
-                                            </abp-dropdown-menu>
+                                            @if (@Model.Languages != null)
+                                            {
+                                                <abp-dropdown-menu>
+                                                    @foreach (var language in Model.Languages)
+                                                    {
+                                                        <abp-dropdown-item href="~/Abp/Languages/Switch?culture=@(language.CultureName)&uiCulture=@(language.UiCultureName)&returnUrl=@(System.Net.WebUtility.UrlEncode(Request.GetEncodedPathAndQuery()))">@language.DisplayName</abp-dropdown-item>
+                                                    }
+                                                </abp-dropdown-menu>
+                                            }
                                         </abp-dropdown>
                                     </div>
                                 </abp-column>
-
                             </abp-row>
                             <hr class="m-4" />
-
                             <abp-row>
-
-                                @foreach (var application in Model.Applications)
+                                @if (Model.Applications != null)
                                 {
-                                    <abp-column size-md="_4" class="mb-2">
-                                        <abp-card>
-                                            <abp-card-body>
-
-                                                @if (!application.LogoUri.IsNullOrEmpty())
-                                                {
-                                                    <div class="mx-auto">
-                                                        <img src="@application.LogoUri" style="height:64px" class="mb-3" />
+                                    foreach (var application in Model.Applications)
+                                    {
+                                        <abp-column size-md="@Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Grid.ColumnSize._4" class="mb-2">
+                                            <abp-card>
+                                                <abp-card-body>
+
+                                                    @if (!application.LogoUri.IsNullOrEmpty())
+                                                    {
+                                                        <div class="mx-auto">
+                                                            <img src="@application.LogoUri" style="height:64px" class="mb-3"/>
+                                                        </div>
+                                                    }
+
+                                                    <h4>@application.DisplayName</h4>
+                                                    <span class="text-muted">@application.ClientUri</span>
+                                                    <div class="mt-1">
+                                                        <a abp-button="@Volo.Abp.AspNetCore.Mvc.UI.Bootstrap.TagHelpers.Button.AbpButtonType.Outline_Secondary" href="@application.ClientUri">@L["Visit"]</a>
                                                     </div>
-                                                }
-
-                                                <h4>@application.DisplayName</h4>
-                                                <span class="text-muted">@application.ClientUri</span>
-                                                <div class="mt-1">
-                                                    <a abp-button="Outline_Secondary" href="@application.ClientUri">@L["Visit"]</a>
-                                                </div>
-                                            </abp-card-body>
-                                        </abp-card>
-                                    </abp-column>
+                                                </abp-card-body>
+                                            </abp-card>
+                                        </abp-column>
+                                    }
                                 }
-
                             </abp-row>
                         </div>
-
                     </abp-card-body>
-
                 </abp-card>
             </div>
-
         </abp-row>
     </div>
-</div>
\ No newline at end of file
+</div>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/Pages/Index.cshtml.cs b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/Pages/Index.cshtml.cs
index b700bdd9bb..d734388689 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/Pages/Index.cshtml.cs
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.AuthServer/Pages/Index.cshtml.cs
@@ -9,11 +9,11 @@ namespace MyCompanyName.MyProjectName.Pages;
 
 public class IndexModel : AbpPageModel
 {
-    public List<OpenIddictApplication> Applications { get; protected set; }
+    public List<OpenIddictApplication>? Applications { get; protected set; }
 
-    public IReadOnlyList<LanguageInfo> Languages { get; protected set; }
+    public IReadOnlyList<LanguageInfo>? Languages { get; protected set; }
 
-    public string CurrentLanguage { get; protected set; }
+    public string? CurrentLanguage { get; protected set; }
 
     protected IOpenIddictApplicationRepository OpenIdApplicationRepository { get; }
 
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server.Tiered/MyCompanyName.MyProjectName.Blazor.Server.Tiered.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server.Tiered/MyCompanyName.MyProjectName.Blazor.Server.Tiered.csproj
index 832bd8d7ba..b67ef63875 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server.Tiered/MyCompanyName.MyProjectName.Blazor.Server.Tiered.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server.Tiered/MyCompanyName.MyProjectName.Blazor.Server.Tiered.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
     <GenerateBindingRedirectsOutputType>true</GenerateBindingRedirectsOutputType>
     <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj
index eb34741aa4..01766b2110 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
     <GenerateBindingRedirectsOutputType>true</GenerateBindingRedirectsOutputType>
     <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyProjectNameBlazorModule.cs b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyProjectNameBlazorModule.cs
index b4f2e723e3..758b60f74e 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyProjectNameBlazorModule.cs
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyProjectNameBlazorModule.cs
@@ -1,3 +1,4 @@
+using System;
 using System.IO;
 using Blazorise.Bootstrap5;
 using Blazorise.Icons.FontAwesome;
@@ -111,7 +112,7 @@ public class MyProjectNameBlazorModule : AbpModule
         Configure<AppUrlOptions>(options =>
         {
             options.Applications["MVC"].RootUrl = configuration["App:SelfUrl"];
-            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"].Split(','));
+            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"]?.Split(',') ?? Array.Empty<string>());
         });
     }
 
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/MyCompanyName.MyProjectName.Blazor.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/MyCompanyName.MyProjectName.Blazor.csproj
index 53338ee686..481062bd15 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/MyCompanyName.MyProjectName.Blazor.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/MyCompanyName.MyProjectName.Blazor.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <BlazorWebAssemblyLoadAllGlobalizationData>true</BlazorWebAssemblyLoadAllGlobalizationData>
     <!-- <TEMPLATE-REMOVE IF-NOT='PWA'> -->
     <ServiceWorkerAssetsManifest>service-worker-assets.js</ServiceWorkerAssetsManifest>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.DbMigrator/MyCompanyName.MyProjectName.DbMigrator.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.DbMigrator/MyCompanyName.MyProjectName.DbMigrator.csproj
index af519e222a..3c581e3947 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.DbMigrator/MyCompanyName.MyProjectName.DbMigrator.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.DbMigrator/MyCompanyName.MyProjectName.DbMigrator.csproj
@@ -5,6 +5,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain.Shared/MyCompanyName.MyProjectName.Domain.Shared.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain.Shared/MyCompanyName.MyProjectName.Domain.Shared.csproj
index cb7b4cd5bf..d90c6e0a7c 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain.Shared/MyCompanyName.MyProjectName.Domain.Shared.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain.Shared/MyCompanyName.MyProjectName.Domain.Shared.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
     <GenerateEmbeddedFilesManifest>true</GenerateEmbeddedFilesManifest>
   </PropertyGroup>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/Data/MyProjectNameDbMigrationService.cs b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/Data/MyProjectNameDbMigrationService.cs
index dd0e61135d..16ef00af77 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/Data/MyProjectNameDbMigrationService.cs
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/Data/MyProjectNameDbMigrationService.cs
@@ -87,7 +87,7 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         Logger.LogInformation("You can safely end this process...");
     }
 
-    private async Task MigrateDatabaseSchemaAsync(Tenant tenant = null)
+    private async Task MigrateDatabaseSchemaAsync(Tenant? tenant = null)
     {
         Logger.LogInformation(
             $"Migrating schema for {(tenant == null ? "host" : tenant.Name + " tenant")} database...");
@@ -98,7 +98,7 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         }
     }
 
-    private async Task SeedDataAsync(Tenant tenant = null)
+    private async Task SeedDataAsync(Tenant? tenant = null)
     {
         Logger.LogInformation($"Executing {(tenant == null ? "host" : tenant.Name + " tenant")} database seed...");
 
@@ -152,8 +152,7 @@ public class MyProjectNameDbMigrationService : ITransientDependency
     private bool MigrationsFolderExists()
     {
         var dbMigrationsProjectFolder = GetEntityFrameworkCoreProjectFolderPath();
-
-        return Directory.Exists(Path.Combine(dbMigrationsProjectFolder, "Migrations"));
+        return dbMigrationsProjectFolder != null && Directory.Exists(Path.Combine(dbMigrationsProjectFolder, "Migrations"));
     }
 
     private void AddInitialMigration()
@@ -188,7 +187,7 @@ public class MyProjectNameDbMigrationService : ITransientDependency
         }
     }
 
-    private string GetEntityFrameworkCoreProjectFolderPath()
+    private string? GetEntityFrameworkCoreProjectFolderPath()
     {
         var slnDirectoryPath = GetSolutionDirectoryPath();
 
@@ -203,15 +202,15 @@ public class MyProjectNameDbMigrationService : ITransientDependency
             .FirstOrDefault(d => d.EndsWith(".EntityFrameworkCore"));
     }
 
-    private string GetSolutionDirectoryPath()
+    private string? GetSolutionDirectoryPath()
     {
         var currentDirectory = new DirectoryInfo(Directory.GetCurrentDirectory());
 
-        while (Directory.GetParent(currentDirectory.FullName) != null)
+        while (currentDirectory != null && Directory.GetParent(currentDirectory.FullName) != null)
         {
             currentDirectory = Directory.GetParent(currentDirectory.FullName);
 
-            if (Directory.GetFiles(currentDirectory.FullName).FirstOrDefault(f => f.EndsWith(".sln")) != null)
+            if (currentDirectory != null && Directory.GetFiles(currentDirectory.FullName).FirstOrDefault(f => f.EndsWith(".sln")) != null)
             {
                 return currentDirectory.FullName;
             }
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyCompanyName.MyProjectName.Domain.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyCompanyName.MyProjectName.Domain.csproj
index 16f823b3ba..61f9ea3e8d 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyCompanyName.MyProjectName.Domain.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyCompanyName.MyProjectName.Domain.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/OpenIddict/OpenIddictDataSeedContributor.cs b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/OpenIddict/OpenIddictDataSeedContributor.cs
index 804e15d0f2..7a8b8f7bf0 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/OpenIddict/OpenIddictDataSeedContributor.cs
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Domain/OpenIddict/OpenIddictDataSeedContributor.cs
@@ -87,7 +87,7 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
             /* MyProjectName_Web client is only needed if you created a tiered
              * solution. Otherwise, you can delete this client. */
             await CreateApplicationAsync(
-                name: webClientId,
+                name: webClientId!,
                 type: OpenIddictConstants.ClientTypes.Confidential,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Web Application",
@@ -110,7 +110,7 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         {
             var consoleAndAngularClientRootUrl = configurationSection["MyProjectName_App:RootUrl"]?.TrimEnd('/');
             await CreateApplicationAsync(
-                name: consoleAndAngularClientId,
+                name: consoleAndAngularClientId!,
                 type: OpenIddictConstants.ClientTypes.Public,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Console Test / Angular Application",
@@ -133,10 +133,10 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         var blazorClientId = configurationSection["MyProjectName_Blazor:ClientId"];
         if (!blazorClientId.IsNullOrWhiteSpace())
         {
-            var blazorRootUrl = configurationSection["MyProjectName_Blazor:RootUrl"].TrimEnd('/');
+            var blazorRootUrl = configurationSection["MyProjectName_Blazor:RootUrl"]?.TrimEnd('/');
 
             await CreateApplicationAsync(
-                name: blazorClientId,
+                name: blazorClientId!,
                 type: OpenIddictConstants.ClientTypes.Public,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Blazor Application",
@@ -159,7 +159,7 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
             var blazorServerTieredRootUrl = configurationSection["MyProjectName_BlazorServerTiered:RootUrl"].EnsureEndsWith('/');
 
             await CreateApplicationAsync(
-                name: blazorServerTieredClientId,
+                name: blazorServerTieredClientId!,
                 type: OpenIddictConstants.ClientTypes.Confidential,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Blazor Server Application",
@@ -180,10 +180,10 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         var swaggerClientId = configurationSection["MyProjectName_Swagger:ClientId"];
         if (!swaggerClientId.IsNullOrWhiteSpace())
         {
-            var swaggerRootUrl = configurationSection["MyProjectName_Swagger:RootUrl"].TrimEnd('/');
+            var swaggerRootUrl = configurationSection["MyProjectName_Swagger:RootUrl"]?.TrimEnd('/');
 
             await CreateApplicationAsync(
-                name: swaggerClientId,
+                name: swaggerClientId!,
                 type: OpenIddictConstants.ClientTypes.Public,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Swagger Application",
@@ -204,13 +204,13 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         [NotNull] string type,
         [NotNull] string consentType,
         string displayName,
-        string secret,
+        string? secret,
         List<string> grantTypes,
         List<string> scopes,
-        string clientUri = null,
-        string redirectUri = null,
-        string postLogoutRedirectUri = null,
-        List<string> permissions = null)
+        string? clientUri = null,
+        string? redirectUri = null,
+        string? postLogoutRedirectUri = null,
+        List<string>? permissions = null)
     {
         if (!string.IsNullOrEmpty(secret) && string.Equals(type, OpenIddictConstants.ClientTypes.Public, StringComparison.OrdinalIgnoreCase))
         {
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.EntityFrameworkCore/MyCompanyName.MyProjectName.EntityFrameworkCore.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.EntityFrameworkCore/MyCompanyName.MyProjectName.EntityFrameworkCore.csproj
index e8d5b7f7f3..36e3318b68 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.EntityFrameworkCore/MyCompanyName.MyProjectName.EntityFrameworkCore.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.EntityFrameworkCore/MyCompanyName.MyProjectName.EntityFrameworkCore.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Client/MyCompanyName.MyProjectName.HttpApi.Client.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Client/MyCompanyName.MyProjectName.HttpApi.Client.csproj
index b2bd230422..702510363b 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Client/MyCompanyName.MyProjectName.HttpApi.Client.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Client/MyCompanyName.MyProjectName.HttpApi.Client.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Host/MyCompanyName.MyProjectName.HttpApi.Host.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Host/MyCompanyName.MyProjectName.HttpApi.Host.csproj
index 540657184c..d2e831a9e0 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Host/MyCompanyName.MyProjectName.HttpApi.Host.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Host/MyCompanyName.MyProjectName.HttpApi.Host.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
     <PreserveCompilationReferences>true</PreserveCompilationReferences>
     <UserSecretsId>MyCompanyName.MyProjectName-4681b4fd-151f-4221-84a4-929d86723e4c</UserSecretsId>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Host/MyProjectNameHttpApiHostModule.cs b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Host/MyProjectNameHttpApiHostModule.cs
index 0c8ef2c82c..c848b1f774 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Host/MyProjectNameHttpApiHostModule.cs
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Host/MyProjectNameHttpApiHostModule.cs
@@ -155,12 +155,10 @@ public class MyProjectNameHttpApiHostModule : AbpModule
             options.AddDefaultPolicy(builder =>
             {
                 builder
-                    .WithOrigins(
-                        configuration["App:CorsOrigins"]
-                            .Split(",", StringSplitOptions.RemoveEmptyEntries)
-                            .Select(o => o.RemovePostFix("/"))
-                            .ToArray()
-                    )
+                    .WithOrigins(configuration["App:CorsOrigins"]?
+                        .Split(",", StringSplitOptions.RemoveEmptyEntries)
+                        .Select(o => o.RemovePostFix("/"))
+                        .ToArray() ?? Array.Empty<string>())
                     .WithAbpExposedHeaders()
                     .SetIsOriginAllowedToAllowWildcardSubdomains()
                     .AllowAnyHeader()
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.HostWithIds/MyCompanyName.MyProjectName.HttpApi.HostWithIds.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.HostWithIds/MyCompanyName.MyProjectName.HttpApi.HostWithIds.csproj
index 6e72b6879f..abc297b855 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.HostWithIds/MyCompanyName.MyProjectName.HttpApi.HostWithIds.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.HostWithIds/MyCompanyName.MyProjectName.HttpApi.HostWithIds.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
     <PreserveCompilationReferences>true</PreserveCompilationReferences>
     <UserSecretsId>MyCompanyName.MyProjectName-4681b4fd-151f-4221-84a4-929d86723e4c</UserSecretsId>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.HostWithIds/MyProjectNameHttpApiHostModule.cs b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.HostWithIds/MyProjectNameHttpApiHostModule.cs
index a88511db4e..dd79fb773c 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.HostWithIds/MyProjectNameHttpApiHostModule.cs
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.HostWithIds/MyProjectNameHttpApiHostModule.cs
@@ -95,7 +95,7 @@ public class MyProjectNameHttpApiHostModule : AbpModule
         Configure<AppUrlOptions>(options =>
         {
             options.Applications["MVC"].RootUrl = configuration["App:SelfUrl"];
-            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"].Split(','));
+            options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"]?.Split(',') ?? Array.Empty<string>());
 
             options.Applications["Angular"].RootUrl = configuration["App:ClientUrl"];
             options.Applications["Angular"].Urls[AccountUrlNames.PasswordReset] = "account/reset-password";
@@ -155,14 +155,12 @@ public class MyProjectNameHttpApiHostModule : AbpModule
         context.Services.AddCors(options =>
         {
             options.AddDefaultPolicy(builder =>
-               {
+            {
                 builder
-                    .WithOrigins(
-                        configuration["App:CorsOrigins"]
-                            .Split(",", StringSplitOptions.RemoveEmptyEntries)
-                            .Select(o => o.RemovePostFix("/"))
-                            .ToArray()
-                    )
+                    .WithOrigins(configuration["App:CorsOrigins"]?
+                        .Split(",", StringSplitOptions.RemoveEmptyEntries)
+                        .Select(o => o.RemovePostFix("/"))
+                        .ToArray() ?? Array.Empty<string>())
                     .WithAbpExposedHeaders()
                     .SetIsOriginAllowedToAllowWildcardSubdomains()
                     .AllowAnyHeader()
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi/MyCompanyName.MyProjectName.HttpApi.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi/MyCompanyName.MyProjectName.HttpApi.csproj
index 2a585f45a4..08243ccd22 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi/MyCompanyName.MyProjectName.HttpApi.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi/MyCompanyName.MyProjectName.HttpApi.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.MongoDB/MyCompanyName.MyProjectName.MongoDB.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.MongoDB/MyCompanyName.MyProjectName.MongoDB.csproj
index e9f07986e2..e39e4d8082 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.MongoDB/MyCompanyName.MyProjectName.MongoDB.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.MongoDB/MyCompanyName.MyProjectName.MongoDB.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web.Host/MyCompanyName.MyProjectName.Web.Host.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web.Host/MyCompanyName.MyProjectName.Web.Host.csproj
index fe7c773451..4840959fcd 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web.Host/MyCompanyName.MyProjectName.Web.Host.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web.Host/MyCompanyName.MyProjectName.Web.Host.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName.Web</RootNamespace>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web/Menus/MyProjectNameMenuContributor.cs b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web/Menus/MyProjectNameMenuContributor.cs
index 7a85f3ab7e..84f6b391b7 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web/Menus/MyProjectNameMenuContributor.cs
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web/Menus/MyProjectNameMenuContributor.cs
@@ -18,7 +18,7 @@ public class MyProjectNameMenuContributor : IMenuContributor
         }
     }
 
-    private async Task ConfigureMainMenuAsync(MenuConfigurationContext context)
+    private Task ConfigureMainMenuAsync(MenuConfigurationContext context)
     {
         var administration = context.Menu.GetAdministration();
         var l = context.GetLocalizer<MyProjectNameResource>();
@@ -45,5 +45,7 @@ public class MyProjectNameMenuContributor : IMenuContributor
 
         administration.SetSubItemOrder(IdentityMenuNames.GroupName, 2);
         administration.SetSubItemOrder(SettingManagementMenuNames.GroupName, 3);
+
+        return Task.CompletedTask;
     }
 }
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web/MyCompanyName.MyProjectName.Web.csproj b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web/MyCompanyName.MyProjectName.Web.csproj
index 560ba570dd..90f7f56e0a 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web/MyCompanyName.MyProjectName.Web.csproj
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Web/MyCompanyName.MyProjectName.Web.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName.Web</RootNamespace>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
diff --git a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Application.Tests/MyCompanyName.MyProjectName.Application.Tests.csproj b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Application.Tests/MyCompanyName.MyProjectName.Application.Tests.csproj
index ee00e7f04c..12f36a7520 100644
--- a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Application.Tests/MyCompanyName.MyProjectName.Application.Tests.csproj
+++ b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Application.Tests/MyCompanyName.MyProjectName.Application.Tests.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/MyCompanyName.MyProjectName.Domain.Tests.csproj b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/MyCompanyName.MyProjectName.Domain.Tests.csproj
index defd452da5..27d5002e1b 100644
--- a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/MyCompanyName.MyProjectName.Domain.Tests.csproj
+++ b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/MyCompanyName.MyProjectName.Domain.Tests.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/EntityFrameworkCore/MyProjectNameEntityFrameworkCoreTestModule.cs b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/EntityFrameworkCore/MyProjectNameEntityFrameworkCoreTestModule.cs
index d68373b4fb..0a76f9928e 100644
--- a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/EntityFrameworkCore/MyProjectNameEntityFrameworkCoreTestModule.cs
+++ b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/EntityFrameworkCore/MyProjectNameEntityFrameworkCoreTestModule.cs
@@ -17,7 +17,7 @@ namespace MyCompanyName.MyProjectName.EntityFrameworkCore;
     )]
 public class MyProjectNameEntityFrameworkCoreTestModule : AbpModule
 {
-    private SqliteConnection _sqliteConnection;
+    private SqliteConnection? _sqliteConnection;
 
     public override void ConfigureServices(ServiceConfigurationContext context)
     {
@@ -39,7 +39,7 @@ public class MyProjectNameEntityFrameworkCoreTestModule : AbpModule
 
     public override void OnApplicationShutdown(ApplicationShutdownContext context)
     {
-        _sqliteConnection.Dispose();
+        _sqliteConnection?.Dispose();
     }
 
     private static SqliteConnection CreateDatabaseAndGetConnection()
diff --git a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests.csproj b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests.csproj
index 6806868b1c..7b13ac6079 100644
--- a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests.csproj
+++ b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp.csproj b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp.csproj
index 14dd55a22e..d8eff36d42 100644
--- a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp.csproj
+++ b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp.csproj
@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.MongoDB.Tests/MyCompanyName.MyProjectName.MongoDB.Tests.csproj b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.MongoDB.Tests/MyCompanyName.MyProjectName.MongoDB.Tests.csproj
index b9844d6d0f..642c72b84f 100644
--- a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.MongoDB.Tests/MyCompanyName.MyProjectName.MongoDB.Tests.csproj
+++ b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.MongoDB.Tests/MyCompanyName.MyProjectName.MongoDB.Tests.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/MyCompanyName.MyProjectName.TestBase.csproj b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/MyCompanyName.MyProjectName.TestBase.csproj
index 05c7539b52..2a8705b312 100644
--- a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/MyCompanyName.MyProjectName.TestBase.csproj
+++ b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/MyCompanyName.MyProjectName.TestBase.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Security/FakeCurrentPrincipalAccessor.cs b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Security/FakeCurrentPrincipalAccessor.cs
index 717ba2c324..512430a84a 100644
--- a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Security/FakeCurrentPrincipalAccessor.cs
+++ b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Security/FakeCurrentPrincipalAccessor.cs
@@ -13,30 +13,13 @@ public class FakeCurrentPrincipalAccessor : ThreadCurrentPrincipalAccessor
         return GetPrincipal();
     }
 
-    private ClaimsPrincipal _principal;
-
     private ClaimsPrincipal GetPrincipal()
     {
-        if (_principal == null)
+        return new ClaimsPrincipal(new ClaimsIdentity(new List<Claim>
         {
-            lock (this)
-            {
-                if (_principal == null)
-                {
-                    _principal = new ClaimsPrincipal(
-                        new ClaimsIdentity(
-                            new List<Claim>
-                            {
-                                    new Claim(AbpClaimTypes.UserId,"2e701e62-0953-4dd3-910b-dc6cc93ccb0d"),
-                                    new Claim(AbpClaimTypes.UserName,"admin"),
-                                    new Claim(AbpClaimTypes.Email,"admin@abp.io")
-                            }
-                        )
-                    );
-                }
-            }
-        }
-
-        return _principal;
+            new Claim(AbpClaimTypes.UserId, "2e701e62-0953-4dd3-910b-dc6cc93ccb0d"),
+            new Claim(AbpClaimTypes.UserName, "admin"),
+            new Claim(AbpClaimTypes.Email, "admin@abp.io")
+        }));
     }
 }
diff --git a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/MyCompanyName.MyProjectName.Web.Tests.csproj b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/MyCompanyName.MyProjectName.Web.Tests.csproj
index 05193d0987..9bf9d3e1d7 100644
--- a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/MyCompanyName.MyProjectName.Web.Tests.csproj
+++ b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/MyCompanyName.MyProjectName.Web.Tests.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <OutputType>Exe</OutputType>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
diff --git a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/MyProjectNameWebTestBase.cs b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/MyProjectNameWebTestBase.cs
index ae94b2fe6d..9736848b6b 100644
--- a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/MyProjectNameWebTestBase.cs
+++ b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/MyProjectNameWebTestBase.cs
@@ -1,4 +1,5 @@
-using System.Net;
+using System;
+using System.Net;
 using System.Net.Http;
 using System.Text.Json;
 using System.Threading.Tasks;
@@ -14,10 +15,10 @@ public abstract class MyProjectNameWebTestBase : AbpAspNetCoreIntegratedTestBase
     {
         return base
             .CreateHostBuilder()
-            .UseContentRoot(WebContentDirectoryFinder.CalculateContentRootFolder());
+            .UseContentRoot(WebContentDirectoryFinder.CalculateContentRootFolder() ?? throw new InvalidOperationException());
     }
 
-    protected virtual async Task<T> GetResponseAsObjectAsync<T>(string url, HttpStatusCode expectedStatusCode = HttpStatusCode.OK)
+    protected virtual async Task<T?> GetResponseAsObjectAsync<T>(string url, HttpStatusCode expectedStatusCode = HttpStatusCode.OK)
     {
         var strResponse = await GetResponseAsStringAsync(url, expectedStatusCode);
         return JsonSerializer.Deserialize<T>(strResponse, new JsonSerializerOptions(JsonSerializerDefaults.Web));
diff --git a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/WebContentDirectoryFinder.cs b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/WebContentDirectoryFinder.cs
index 4c8c4bfd0c..f0a3149272 100644
--- a/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/WebContentDirectoryFinder.cs
+++ b/templates/app/aspnet-core/test/MyCompanyName.MyProjectName.Web.Tests/WebContentDirectoryFinder.cs
@@ -11,7 +11,7 @@ namespace MyCompanyName.MyProjectName;
 /// </summary>
 public static class WebContentDirectoryFinder
 {
-    public static string CalculateContentRootFolder()
+    public static string? CalculateContentRootFolder()
     {
         var domainAssemblyDirectoryPath =
             Path.GetDirectoryName(typeof(MyProjectNameDomainModule).Assembly.Location);
diff --git a/templates/console/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj b/templates/console/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj
index c25eb1af14..616d70bc3e 100644
--- a/templates/console/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj
+++ b/templates/console/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj
@@ -5,6 +5,7 @@
     <PropertyGroup>
         <OutputType>Exe</OutputType>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
     </PropertyGroup>
 
     <ItemGroup>
diff --git a/templates/maui/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj b/templates/maui/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj
index 205a22c2c9..b36be3895a 100644
--- a/templates/maui/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj
+++ b/templates/maui/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj
@@ -1,12 +1,13 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
 	<Import Project="..\..\common.props" />
-	
+
 	<PropertyGroup>
 		<TargetFrameworks>net7.0-android;net7.0-ios;net7.0-maccatalyst</TargetFrameworks>
 		<TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('windows'))">$(TargetFrameworks);net7.0-windows10.0.19041.0</TargetFrameworks>
 		<!-- Uncomment to also build the tizen app. You will need to install tizen by following this: https://github.com/Samsung/Tizen.NET -->
 		<!-- <TargetFrameworks>$(TargetFrameworks);net7.0-tizen</TargetFrameworks> -->
+		<Nullable>enable</Nullable>
 		<OutputType>Exe</OutputType>
 		<RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
 		<UseMaui>true</UseMaui>
@@ -54,7 +55,7 @@
 		<!-- Raw Assets (also remove the "Resources\Raw" prefix) -->
 		<MauiAsset Include="Resources\Raw\**" LogicalName="%(RecursiveDir)%(Filename)%(Extension)" />
 	</ItemGroup>
-	
+
 	<ItemGroup>
 	  <None Remove="appsettings.json" />
 	  <EmbeddedResource Include="appsettings.json" />
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/MyCompanyName.MyProjectName.AuthServer.csproj b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/MyCompanyName.MyProjectName.AuthServer.csproj
index 13d7c366b4..022889cd58 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/MyCompanyName.MyProjectName.AuthServer.csproj
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/MyCompanyName.MyProjectName.AuthServer.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
     <PreserveCompilationReferences>true</PreserveCompilationReferences>
     <UserSecretsId>MyCompanyName.MyProjectName-c2d31439-b723-48e2-b061-5ebd7aeb6010</UserSecretsId>
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/MyProjectNameAuthServerModule.cs b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/MyProjectNameAuthServerModule.cs
index 8d5967e361..5fef3d79a8 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/MyProjectNameAuthServerModule.cs
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/MyProjectNameAuthServerModule.cs
@@ -175,10 +175,10 @@ public class MyProjectNameAuthServerModule : AbpModule
             {
                 builder
                     .WithOrigins(
-                        configuration["App:CorsOrigins"]
+                        configuration["App:CorsOrigins"]?
                             .Split(",", StringSplitOptions.RemoveEmptyEntries)
                             .Select(o => o.RemovePostFix("/"))
-                            .ToArray()
+                            .ToArray() ?? Array.Empty<string>()
                     )
                     .WithAbpExposedHeaders()
                     .SetIsOriginAllowedToAllowWildcardSubdomains()
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/OpenIddict/OpenIddictDataSeedContributor.cs b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/OpenIddict/OpenIddictDataSeedContributor.cs
index 7ecafc5f6a..dea53ea554 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/OpenIddict/OpenIddictDataSeedContributor.cs
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.AuthServer/OpenIddict/OpenIddictDataSeedContributor.cs
@@ -86,7 +86,7 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
             /* MyProjectName_Web client is only needed if you created a tiered
              * solution. Otherwise, you can delete this client. */
             await CreateApplicationAsync(
-                name: webClientId,
+                name: webClientId!,
                 type: OpenIddictConstants.ClientTypes.Confidential,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Web Application",
@@ -108,7 +108,7 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         {
             var consoleAndAngularClientRootUrl = configurationSection["MyProjectName_App:RootUrl"]?.TrimEnd('/');
             await CreateApplicationAsync(
-                name: consoleAndAngularClientId,
+                name: consoleAndAngularClientId!,
                 type: OpenIddictConstants.ClientTypes.Public,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Console Test / Angular Application",
@@ -130,10 +130,10 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         var blazorClientId = configurationSection["MyProjectName_Blazor:ClientId"];
         if (!blazorClientId.IsNullOrWhiteSpace())
         {
-            var blazorRootUrl = configurationSection["MyProjectName_Blazor:RootUrl"].TrimEnd('/');
+            var blazorRootUrl = configurationSection["MyProjectName_Blazor:RootUrl"]?.TrimEnd('/');
 
             await CreateApplicationAsync(
-                name: blazorClientId,
+                name: blazorClientId!,
                 type: OpenIddictConstants.ClientTypes.Public,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Blazor Application",
@@ -152,10 +152,10 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         var swaggerClientId = configurationSection["MyProjectName_Swagger:ClientId"];
         if (!swaggerClientId.IsNullOrWhiteSpace())
         {
-            var swaggerRootUrl = configurationSection["MyProjectName_Swagger:RootUrl"].TrimEnd('/');
+            var swaggerRootUrl = configurationSection["MyProjectName_Swagger:RootUrl"]?.TrimEnd('/');
 
             await CreateApplicationAsync(
-                name: swaggerClientId,
+                name: swaggerClientId!,
                 type: OpenIddictConstants.ClientTypes.Public,
                 consentType: OpenIddictConstants.ConsentTypes.Implicit,
                 displayName: "Swagger Application",
@@ -175,12 +175,12 @@ public class OpenIddictDataSeedContributor : IDataSeedContributor, ITransientDep
         [NotNull] string type,
         [NotNull] string consentType,
         string displayName,
-        string secret,
+        string? secret,
         List<string> grantTypes,
         List<string> scopes,
-        string redirectUri = null,
-        string postLogoutRedirectUri = null,
-        List<string> permissions = null)
+        string? redirectUri = null,
+        string? postLogoutRedirectUri = null,
+        List<string>? permissions = null)
     {
         if (!string.IsNullOrEmpty(secret) && string.Equals(type, OpenIddictConstants.ClientTypes.Public, StringComparison.OrdinalIgnoreCase))
         {
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Host/MyCompanyName.MyProjectName.Blazor.Host.csproj b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Host/MyCompanyName.MyProjectName.Blazor.Host.csproj
index 5177f6af11..89d0af9e3c 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Host/MyCompanyName.MyProjectName.Blazor.Host.csproj
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Host/MyCompanyName.MyProjectName.Blazor.Host.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <BlazorWebAssemblyLoadAllGlobalizationData>true</BlazorWebAssemblyLoadAllGlobalizationData>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Host/Pages/Index.razor b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Host/Pages/Index.razor
index 1140cddeff..cddd608f45 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Host/Pages/Index.razor
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Host/Pages/Index.razor
@@ -47,12 +47,12 @@
 
 @code
 {
-    private IEnumerable<Claim> _claims;
+    private IEnumerable<Claim>? _claims;
 
-    protected async override Task OnInitializedAsync()
+    protected override async Task OnInitializedAsync()
     {
         var authState = await AuthenticationStateProvider.GetAuthenticationStateAsync();
-        if (authState.User.Identity.IsAuthenticated)
+        if (authState.User.Identity != null && authState.User.Identity.IsAuthenticated)
         {
             _claims = authState.User.Claims;
         }
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/MyCompanyName.MyProjectName.Blazor.Server.Host.csproj b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/MyCompanyName.MyProjectName.Blazor.Server.Host.csproj
index 4557540843..ce942ef18c 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/MyCompanyName.MyProjectName.Blazor.Server.Host.csproj
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/MyCompanyName.MyProjectName.Blazor.Server.Host.csproj
@@ -4,6 +4,7 @@
 
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
         <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
         <GenerateBindingRedirectsOutputType>true</GenerateBindingRedirectsOutputType>
         <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles>
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/MyProjectNameBlazorHostModule.cs b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/MyProjectNameBlazorHostModule.cs
index 46bb89e1b8..1dc8d7d14d 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/MyProjectNameBlazorHostModule.cs
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/MyProjectNameBlazorHostModule.cs
@@ -209,7 +209,7 @@ public class MyProjectNameBlazorHostModule : AbpModule
             Configure<AppUrlOptions>(options =>
             {
                 options.Applications["MVC"].RootUrl = configuration["App:SelfUrl"];
-                options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"].Split(','));
+                options.RedirectAllowedUrls.AddRange(configuration["App:RedirectAllowedUrls"]?.Split(',') ?? Array.Empty<string>());
             });
 
 #if DEBUG
@@ -217,7 +217,7 @@ public class MyProjectNameBlazorHostModule : AbpModule
 #endif
     }
 
-    public async override Task OnApplicationInitializationAsync(ApplicationInitializationContext context)
+    public override async Task OnApplicationInitializationAsync(ApplicationInitializationContext context)
     {
         var env = context.GetEnvironment();
         var app = context.GetApplicationBuilder();
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/Pages/Index.razor b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/Pages/Index.razor
index 0c9af64456..a7aebf6ded 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/Pages/Index.razor
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Blazor.Server.Host/Pages/Index.razor
@@ -1,8 +1,5 @@
 @page "/"
-@using Volo.Abp.MultiTenancy
 @inherits MyProjectNameComponentBase
-@inject ICurrentTenant CurrentTenant
-@inject AuthenticationStateProvider AuthenticationStateProvider
 <div class="container">
     <div class="p-5 text-center">
 
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Host.Shared/MyCompanyName.MyProjectName.Host.Shared.csproj b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Host.Shared/MyCompanyName.MyProjectName.Host.Shared.csproj
index 8cb063a10b..0cd160826b 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Host.Shared/MyCompanyName.MyProjectName.Host.Shared.csproj
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Host.Shared/MyCompanyName.MyProjectName.Host.Shared.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.HttpApi.Host/MyCompanyName.MyProjectName.HttpApi.Host.csproj b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.HttpApi.Host/MyCompanyName.MyProjectName.HttpApi.Host.csproj
index 34f688c58c..ebe9f5c565 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.HttpApi.Host/MyCompanyName.MyProjectName.HttpApi.Host.csproj
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.HttpApi.Host/MyCompanyName.MyProjectName.HttpApi.Host.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
     <PreserveCompilationReferences>true</PreserveCompilationReferences>
     <UserSecretsId>MyCompanyName.MyProjectName-c2d31439-b723-48e2-b061-5ebd7aeb6010</UserSecretsId>
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.HttpApi.Host/MyProjectNameHttpApiHostModule.cs b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.HttpApi.Host/MyProjectNameHttpApiHostModule.cs
index a736a9ca0f..bc1ec583b6 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.HttpApi.Host/MyProjectNameHttpApiHostModule.cs
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.HttpApi.Host/MyProjectNameHttpApiHostModule.cs
@@ -143,10 +143,10 @@ public class MyProjectNameHttpApiHostModule : AbpModule
             {
                 builder
                     .WithOrigins(
-                        configuration["App:CorsOrigins"]
+                        configuration["App:CorsOrigins"]?
                             .Split(",", StringSplitOptions.RemoveEmptyEntries)
                             .Select(o => o.RemovePostFix("/"))
-                            .ToArray()
+                            .ToArray() ?? Array.Empty<string>()
                     )
                     .WithAbpExposedHeaders()
                     .SetIsOriginAllowedToAllowWildcardSubdomains()
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Web.Host/MyCompanyName.MyProjectName.Web.Host.csproj b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Web.Host/MyCompanyName.MyProjectName.Web.Host.csproj
index f0eb77f53f..efb9ebd119 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Web.Host/MyCompanyName.MyProjectName.Web.Host.csproj
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Web.Host/MyCompanyName.MyProjectName.Web.Host.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
     <PreserveCompilationReferences>true</PreserveCompilationReferences>
     <UserSecretsId>MyCompanyName.MyProjectName-c2d31439-b723-48e2-b061-5ebd7aeb6010</UserSecretsId>
diff --git a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Web.Unified/MyCompanyName.MyProjectName.Web.Unified.csproj b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Web.Unified/MyCompanyName.MyProjectName.Web.Unified.csproj
index 1a37ef59ea..2d0959a426 100644
--- a/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Web.Unified/MyCompanyName.MyProjectName.Web.Unified.csproj
+++ b/templates/module/aspnet-core/host/MyCompanyName.MyProjectName.Web.Unified/MyCompanyName.MyProjectName.Web.Unified.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
     <PreserveCompilationReferences>true</PreserveCompilationReferences>
     <UserSecretsId>MyCompanyName.MyProjectName-c2d31439-b723-48e2-b061-5ebd7aeb6010</UserSecretsId>
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Application.Contracts/MyCompanyName.MyProjectName.Application.Contracts.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Application.Contracts/MyCompanyName.MyProjectName.Application.Contracts.csproj
index c572d2bee1..341d5640d8 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Application.Contracts/MyCompanyName.MyProjectName.Application.Contracts.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Application.Contracts/MyCompanyName.MyProjectName.Application.Contracts.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Application/MyCompanyName.MyProjectName.Application.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Application/MyCompanyName.MyProjectName.Application.csproj
index 82e5ec1a94..ddf2e84283 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Application/MyCompanyName.MyProjectName.Application.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Application/MyCompanyName.MyProjectName.Application.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj
index fb7721dabc..828dbeda41 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.Server/MyCompanyName.MyProjectName.Blazor.Server.csproj
@@ -4,6 +4,7 @@
 
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
     </PropertyGroup>
 
     <ItemGroup>
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.WebAssembly/MyCompanyName.MyProjectName.Blazor.WebAssembly.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.WebAssembly/MyCompanyName.MyProjectName.Blazor.WebAssembly.csproj
index 7a47626fc9..e89a3d035c 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.WebAssembly/MyCompanyName.MyProjectName.Blazor.WebAssembly.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor.WebAssembly/MyCompanyName.MyProjectName.Blazor.WebAssembly.csproj
@@ -4,8 +4,9 @@
 
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
     </PropertyGroup>
-    
+
     <ItemGroup>
         <ProjectReference Include="..\..\..\..\..\framework\src\Volo.Abp.AspNetCore.Components.WebAssembly.Theming\Volo.Abp.AspNetCore.Components.WebAssembly.Theming.csproj"/>
     </ItemGroup>
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/MyCompanyName.MyProjectName.Blazor.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/MyCompanyName.MyProjectName.Blazor.csproj
index c5bf783de3..7ac06b0881 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/MyCompanyName.MyProjectName.Blazor.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/MyCompanyName.MyProjectName.Blazor.csproj
@@ -4,6 +4,7 @@
 
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
     </PropertyGroup>
 
     <ItemGroup>
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain.Shared/MyCompanyName.MyProjectName.Domain.Shared.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain.Shared/MyCompanyName.MyProjectName.Domain.Shared.csproj
index 70f7079e3f..619813ab46 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain.Shared/MyCompanyName.MyProjectName.Domain.Shared.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain.Shared/MyCompanyName.MyProjectName.Domain.Shared.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
     <GenerateEmbeddedFilesManifest>true</GenerateEmbeddedFilesManifest>
   </PropertyGroup>
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyCompanyName.MyProjectName.Domain.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyCompanyName.MyProjectName.Domain.csproj
index 2902edbe3d..aa33eecfda 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyCompanyName.MyProjectName.Domain.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyCompanyName.MyProjectName.Domain.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyProjectNameDbProperties.cs b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyProjectNameDbProperties.cs
index 2ac3e3f9e3..1fa7ecaf35 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyProjectNameDbProperties.cs
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Domain/MyProjectNameDbProperties.cs
@@ -4,7 +4,7 @@ public static class MyProjectNameDbProperties
 {
     public static string DbTablePrefix { get; set; } = "MyProjectName";
 
-    public static string DbSchema { get; set; } = null;
+    public static string? DbSchema { get; set; } = null;
 
     public const string ConnectionStringName = "MyProjectName";
 }
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.EntityFrameworkCore/MyCompanyName.MyProjectName.EntityFrameworkCore.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.EntityFrameworkCore/MyCompanyName.MyProjectName.EntityFrameworkCore.csproj
index 5c50aed0f2..a1511f1a51 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.EntityFrameworkCore/MyCompanyName.MyProjectName.EntityFrameworkCore.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.EntityFrameworkCore/MyCompanyName.MyProjectName.EntityFrameworkCore.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Client/MyCompanyName.MyProjectName.HttpApi.Client.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Client/MyCompanyName.MyProjectName.HttpApi.Client.csproj
index 8486d3f247..a05ea0e71a 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Client/MyCompanyName.MyProjectName.HttpApi.Client.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi.Client/MyCompanyName.MyProjectName.HttpApi.Client.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi/MyCompanyName.MyProjectName.HttpApi.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi/MyCompanyName.MyProjectName.HttpApi.csproj
index 411049eb72..9edd4d08cc 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi/MyCompanyName.MyProjectName.HttpApi.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.HttpApi/MyCompanyName.MyProjectName.HttpApi.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Installer/MyCompanyName.MyProjectName.Installer.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Installer/MyCompanyName.MyProjectName.Installer.csproj
index 5dcb0e44df..64f9efa66d 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Installer/MyCompanyName.MyProjectName.Installer.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Installer/MyCompanyName.MyProjectName.Installer.csproj
@@ -4,6 +4,7 @@
 
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
+        <Nullable>enable</Nullable>
         <GenerateEmbeddedFilesManifest>true</GenerateEmbeddedFilesManifest>
         <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
     </PropertyGroup>
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.MongoDB/MyCompanyName.MyProjectName.MongoDB.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.MongoDB/MyCompanyName.MyProjectName.MongoDB.csproj
index 654c7a14f3..95f1137ebb 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.MongoDB/MyCompanyName.MyProjectName.MongoDB.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.MongoDB/MyCompanyName.MyProjectName.MongoDB.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Web/MyCompanyName.MyProjectName.Web.csproj b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Web/MyCompanyName.MyProjectName.Web.csproj
index ea75e4e731..8985ad3713 100644
--- a/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Web/MyCompanyName.MyProjectName.Web.csproj
+++ b/templates/module/aspnet-core/src/MyCompanyName.MyProjectName.Web/MyCompanyName.MyProjectName.Web.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
     <IsPackable>true</IsPackable>
     <OutputType>Library</OutputType>
diff --git a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Application.Tests/MyCompanyName.MyProjectName.Application.Tests.csproj b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Application.Tests/MyCompanyName.MyProjectName.Application.Tests.csproj
index ae01d6eff1..d472d6a29f 100644
--- a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Application.Tests/MyCompanyName.MyProjectName.Application.Tests.csproj
+++ b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Application.Tests/MyCompanyName.MyProjectName.Application.Tests.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/MyCompanyName.MyProjectName.Domain.Tests.csproj b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/MyCompanyName.MyProjectName.Domain.Tests.csproj
index 5edd4ddc4f..c13f03f701 100644
--- a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/MyCompanyName.MyProjectName.Domain.Tests.csproj
+++ b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/MyCompanyName.MyProjectName.Domain.Tests.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/Samples/SampleManager_Tests.cs b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/Samples/SampleManager_Tests.cs
index 24254b2628..d9c35ff3f9 100644
--- a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/Samples/SampleManager_Tests.cs
+++ b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.Domain.Tests/Samples/SampleManager_Tests.cs
@@ -13,8 +13,8 @@ public class SampleManager_Tests : MyProjectNameDomainTestBase
     }
 
     [Fact]
-    public async Task Method1Async()
+    public Task Method1Async()
     {
-
+        return Task.CompletedTask;
     }
 }
diff --git a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests.csproj b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests.csproj
index 69baaac85e..e4f7896f97 100644
--- a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests.csproj
+++ b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests/MyCompanyName.MyProjectName.EntityFrameworkCore.Tests.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp.csproj b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp.csproj
index 3c75dcf3c9..450625e048 100644
--- a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp.csproj
+++ b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp/MyCompanyName.MyProjectName.HttpApi.Client.ConsoleTestApp.csproj
@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.MongoDB.Tests/MyCompanyName.MyProjectName.MongoDB.Tests.csproj b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.MongoDB.Tests/MyCompanyName.MyProjectName.MongoDB.Tests.csproj
index 1dffc4d80f..ef1b43437b 100644
--- a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.MongoDB.Tests/MyCompanyName.MyProjectName.MongoDB.Tests.csproj
+++ b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.MongoDB.Tests/MyCompanyName.MyProjectName.MongoDB.Tests.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/MyCompanyName.MyProjectName.TestBase.csproj b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/MyCompanyName.MyProjectName.TestBase.csproj
index 0ec8bf147b..9cef5098e7 100644
--- a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/MyCompanyName.MyProjectName.TestBase.csproj
+++ b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/MyCompanyName.MyProjectName.TestBase.csproj
@@ -4,6 +4,7 @@
 
   <PropertyGroup>
     <TargetFramework>net7.0</TargetFramework>
+    <Nullable>enable</Nullable>
     <RootNamespace>MyCompanyName.MyProjectName</RootNamespace>
   </PropertyGroup>
 
diff --git a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Samples/SampleRepository_Tests.cs b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Samples/SampleRepository_Tests.cs
index 738c202b90..acfc4f7139 100644
--- a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Samples/SampleRepository_Tests.cs
+++ b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Samples/SampleRepository_Tests.cs
@@ -19,8 +19,8 @@ public abstract class SampleRepository_Tests<TStartupModule> : MyProjectNameTest
     }
 
     [Fact]
-    public async Task Method1Async()
+    public Task Method1Async()
     {
-
+        return Task.CompletedTask;
     }
 }
diff --git a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Security/FakeCurrentPrincipalAccessor.cs b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Security/FakeCurrentPrincipalAccessor.cs
index 717ba2c324..45db4c6afe 100644
--- a/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Security/FakeCurrentPrincipalAccessor.cs
+++ b/templates/module/aspnet-core/test/MyCompanyName.MyProjectName.TestBase/Security/FakeCurrentPrincipalAccessor.cs
@@ -13,30 +13,15 @@ public class FakeCurrentPrincipalAccessor : ThreadCurrentPrincipalAccessor
         return GetPrincipal();
     }
 
-    private ClaimsPrincipal _principal;
-
     private ClaimsPrincipal GetPrincipal()
     {
-        if (_principal == null)
-        {
-            lock (this)
-            {
-                if (_principal == null)
+        return new ClaimsPrincipal(new ClaimsIdentity(new List<Claim>
                 {
-                    _principal = new ClaimsPrincipal(
-                        new ClaimsIdentity(
-                            new List<Claim>
-                            {
-                                    new Claim(AbpClaimTypes.UserId,"2e701e62-0953-4dd3-910b-dc6cc93ccb0d"),
-                                    new Claim(AbpClaimTypes.UserName,"admin"),
-                                    new Claim(AbpClaimTypes.Email,"admin@abp.io")
-                            }
-                        )
-                    );
+                    new Claim(AbpClaimTypes.UserId, "2e701e62-0953-4dd3-910b-dc6cc93ccb0d"),
+                    new Claim(AbpClaimTypes.UserName, "admin"),
+                    new Claim(AbpClaimTypes.Email, "admin@abp.io")
                 }
-            }
-        }
-
-        return _principal;
+            )
+        );
     }
 }
diff --git a/templates/wpf/src/MyCompanyName.MyProjectName/App.xaml.cs b/templates/wpf/src/MyCompanyName.MyProjectName/App.xaml.cs
index 21124d6400..c089f1f00a 100644
--- a/templates/wpf/src/MyCompanyName.MyProjectName/App.xaml.cs
+++ b/templates/wpf/src/MyCompanyName.MyProjectName/App.xaml.cs
@@ -12,9 +12,9 @@ namespace MyCompanyName.MyProjectName;
 /// </summary>
 public partial class App : Application
 {
-    private IAbpApplicationWithInternalServiceProvider _abpApplication;
+    private IAbpApplicationWithInternalServiceProvider? _abpApplication;
 
-    protected async override void OnStartup(StartupEventArgs e)
+    protected override async void OnStartup(StartupEventArgs e)
     {
         Log.Logger = new LoggerConfiguration()
 #if DEBUG
@@ -48,9 +48,12 @@ public partial class App : Application
         }
     }
 
-    protected async override void OnExit(ExitEventArgs e)
+    protected override async void OnExit(ExitEventArgs e)
     {
-        await _abpApplication.ShutdownAsync();
+        if (_abpApplication != null)
+        {
+            await _abpApplication.ShutdownAsync();
+        }
         Log.CloseAndFlush();
     }
 }
diff --git a/templates/wpf/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj b/templates/wpf/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj
index 0f3b9ee973..4329eec058 100644
--- a/templates/wpf/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj
+++ b/templates/wpf/src/MyCompanyName.MyProjectName/MyCompanyName.MyProjectName.csproj
@@ -5,6 +5,7 @@
     <PropertyGroup>
         <OutputType>WinExe</OutputType>
         <TargetFramework>net7.0-windows</TargetFramework>
+        <Nullable>enable</Nullable>
         <UseWPF>true</UseWPF>
     </PropertyGroup>