diff --git a/framework/src/Volo.Abp.Data/Volo/Abp/Data/AppliedDatabaseMigrationsEto.cs b/framework/src/Volo.Abp.Data/Volo/Abp/Data/AppliedDatabaseMigrationsEto.cs
index 739571e241..53fae25737 100644
--- a/framework/src/Volo.Abp.Data/Volo/Abp/Data/AppliedDatabaseMigrationsEto.cs
+++ b/framework/src/Volo.Abp.Data/Volo/Abp/Data/AppliedDatabaseMigrationsEto.cs
@@ -7,6 +7,6 @@ namespace Volo.Abp.Data;
 [EventName("abp.data.applied_database_migrations")]
 public class AppliedDatabaseMigrationsEto
 {
-    public string DatabaseName { get; set; }
+    public string DatabaseName { get; set; } = default!;
     public Guid? TenantId { get; set; }
 }
\ No newline at end of file
diff --git a/framework/src/Volo.Abp.UI/Volo.Abp.UI.csproj b/framework/src/Volo.Abp.UI/Volo.Abp.UI.csproj
index 0cf11fba78..b0bd555c96 100644
--- a/framework/src/Volo.Abp.UI/Volo.Abp.UI.csproj
+++ b/framework/src/Volo.Abp.UI/Volo.Abp.UI.csproj
@@ -5,6 +5,8 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;net7.0</TargetFrameworks>
+    <Nullable>enable</Nullable>
+    <WarningsAsErrors>Nullable</WarningsAsErrors>
     <AssemblyName>Volo.Abp.UI</AssemblyName>
     <PackageId>Volo.Abp.UI</PackageId>
     <AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
diff --git a/framework/src/Volo.Abp.UI/Volo/Abp/Ui/Branding/DefaultBrandingProvider.cs b/framework/src/Volo.Abp.UI/Volo/Abp/Ui/Branding/DefaultBrandingProvider.cs
index 785c03a0e1..fcb1a7545e 100644
--- a/framework/src/Volo.Abp.UI/Volo/Abp/Ui/Branding/DefaultBrandingProvider.cs
+++ b/framework/src/Volo.Abp.UI/Volo/Abp/Ui/Branding/DefaultBrandingProvider.cs
@@ -6,7 +6,7 @@ public class DefaultBrandingProvider : IBrandingProvider, ITransientDependency
 {
     public virtual string AppName => "MyApplication";
 
-    public virtual string LogoUrl => null;
+    public virtual string? LogoUrl => null;
 
-    public virtual string LogoReverseUrl => null;
+    public virtual string? LogoReverseUrl => null;
 }
diff --git a/framework/src/Volo.Abp.UI/Volo/Abp/Ui/Branding/IBrandingProvider.cs b/framework/src/Volo.Abp.UI/Volo/Abp/Ui/Branding/IBrandingProvider.cs
index 95085f56a6..f37ee09df1 100644
--- a/framework/src/Volo.Abp.UI/Volo/Abp/Ui/Branding/IBrandingProvider.cs
+++ b/framework/src/Volo.Abp.UI/Volo/Abp/Ui/Branding/IBrandingProvider.cs
@@ -7,10 +7,10 @@ public interface IBrandingProvider
     /// <summary>
     /// Logo on white background
     /// </summary>
-    string LogoUrl { get; }
+    string? LogoUrl { get; }
 
     /// <summary>
     /// Logo on dark background
     /// </summary>
-    string LogoReverseUrl { get; }
+    string? LogoReverseUrl { get; }
 }
diff --git a/framework/src/Volo.Abp.UI/Volo/Abp/Ui/LayoutHooks/AbpLayoutHookOptions.cs b/framework/src/Volo.Abp.UI/Volo/Abp/Ui/LayoutHooks/AbpLayoutHookOptions.cs
index d5ba4aa239..b76e713a8e 100644
--- a/framework/src/Volo.Abp.UI/Volo/Abp/Ui/LayoutHooks/AbpLayoutHookOptions.cs
+++ b/framework/src/Volo.Abp.UI/Volo/Abp/Ui/LayoutHooks/AbpLayoutHookOptions.cs
@@ -12,7 +12,7 @@ public class AbpLayoutHookOptions
         Hooks = new Dictionary<string, List<LayoutHookInfo>>();
     }
 
-    public AbpLayoutHookOptions Add(string name, Type componentType, string layout = null)
+    public AbpLayoutHookOptions Add(string name, Type componentType, string? layout = null)
     {
         Hooks
             .GetOrAdd(name, () => new List<LayoutHookInfo>())
diff --git a/framework/src/Volo.Abp.UI/Volo/Abp/Ui/LayoutHooks/LayoutHookInfo.cs b/framework/src/Volo.Abp.UI/Volo/Abp/Ui/LayoutHooks/LayoutHookInfo.cs
index db4ca39466..bb5c8e4801 100644
--- a/framework/src/Volo.Abp.UI/Volo/Abp/Ui/LayoutHooks/LayoutHookInfo.cs
+++ b/framework/src/Volo.Abp.UI/Volo/Abp/Ui/LayoutHooks/LayoutHookInfo.cs
@@ -13,9 +13,9 @@ public class LayoutHookInfo
     /// Specifies the layout name to apply this hook.
     /// null indicates that this hook will be applied to all layouts.
     /// </summary>
-    public string Layout { get; }
+    public string? Layout { get; }
 
-    public LayoutHookInfo(Type componentType, string layout = null)
+    public LayoutHookInfo(Type componentType, string? layout = null)
     {
         ComponentType = componentType;
         Layout = layout;