Move Overriding a Page Model to UI side.

docs/en/Customizing-Application-Modules-Overriding-Services.md

@@ -157,42 +157,6 @@ This example class inherits from the `IdentityUserManager` [domain service](Doma
 
 Check the [localization system](Localization.md) to learn how to localize the error messages.
 
-### Example: Overriding a Page Model
-
-````csharp
-using System.Threading.Tasks;
-using Microsoft.AspNetCore.Mvc;
-using Volo.Abp.DependencyInjection;
-using Volo.Abp.Identity;
-using Volo.Abp.Identity.Web.Pages.Identity.Users;
-
-namespace Acme.BookStore.Web.Pages.Identity.Users
-{
-    [Dependency(ReplaceServices = true)]
-    [ExposeServices(typeof(EditModalModel))]
-    public class MyEditModalModel : EditModalModel
-    {
-        public MyEditModalModel(
-            IIdentityUserAppService identityUserAppService, 
-            IIdentityRoleAppService identityRoleAppService
-            ) : base(
-                identityUserAppService, 
-                identityRoleAppService)
-        {
-        }
-
-        public override async Task<IActionResult> OnPostAsync()
-        {
-            //TODO: Additional logic
-            await base.OnPostAsync();
-            //TODO: Additional logic
-        }
-    }
-}
-````
-
-This class replaces `EditModalModel` for the users and overrides the `OnPostAsync` method.
-
 ### Overriding Other Classes
 
 Overriding controllers, framework services, view component classes and any other type of classes registered to dependency injection can be overridden just like the examples above.

docs/en/UI/AspNetCore/Customization-User-Interface.md

@@ -1,4 +1,40 @@
 # ASP.NET Core (MVC / Razor Pages) User Interface Customization Guide
 
-TODO
+This document explains how to override the user interface of a depended [application module](../../Modules/Index.md) for ASP.NET Core MVC / Razor Page applications.
+
+## Overriding a Page Model
+
+````csharp
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc;
+using Volo.Abp.DependencyInjection;
+using Volo.Abp.Identity;
+using Volo.Abp.Identity.Web.Pages.Identity.Users;
+
+namespace Acme.BookStore.Web.Pages.Identity.Users
+{
+    [Dependency(ReplaceServices = true)]
+    [ExposeServices(typeof(EditModalModel))]
+    public class MyEditModalModel : EditModalModel
+    {
+        public MyEditModalModel(
+            IIdentityUserAppService identityUserAppService, 
+            IIdentityRoleAppService identityRoleAppService
+            ) : base(
+                identityUserAppService, 
+                identityRoleAppService)
+        {
+        }
+
+        public override async Task<IActionResult> OnPostAsync()
+        {
+            //TODO: Additional logic
+            await base.OnPostAsync();
+            //TODO: Additional logic
+        }
+    }
+}
+````
+
+This class replaces `EditModalModel` for the users and overrides the `OnPostAsync` method.