From b46bef662a9aabd62e0e78168cb27024e100c82d Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 19 Mar 2026 13:17:04 +0000
Subject: [PATCH 1/3] Initial plan


From 64e0a4ce29949c7252f357a831e10ed84c7e14bd Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 19 Mar 2026 13:19:02 +0000
Subject: [PATCH 2/3] docs: add partial class approach to Blazor code-behind
 section

Co-authored-by: BillWagner <493969+BillWagner@users.noreply.github.com>
---
 .../components.md                             | 37 +++++++++++++++++--
 1 file changed, 34 insertions(+), 3 deletions(-)

diff --git a/docs/architecture/blazor-for-web-forms-developers/components.md b/docs/architecture/blazor-for-web-forms-developers/components.md
index ae826a41d1dd8..3e877b7879f3a 100644
--- a/docs/architecture/blazor-for-web-forms-developers/components.md
+++ b/docs/architecture/blazor-for-web-forms-developers/components.md
@@ -4,8 +4,9 @@ description: Learn how to build reusable UI components with Blazor and how they
 author: danroth27
 ms.author: daroth
 no-loc: [Blazor]
-ms.date: 04/11/2022
+ms.date: 03/19/2026
 ms.custom: sfi-ropc-nochange
+ai-usage: ai-assisted
 ---
 # Build reusable UI components with Blazor
 
@@ -663,7 +664,37 @@ The output of this component looks like this:
 
 ## Code-behind
 
-A Razor component is typically authored in a single *.razor* file. However, it's also possible to separate the code and markup using a code-behind file. To use a component file, add a C# file that matches the file name of the component file but with a *.cs* extension added (*Counter.razor.cs*). Use the C# file to define a base class for the component. You can name the base class anything you'd like, but it's common to name the class the same as the component class, but with a `Base` extension added (`CounterBase`). The component-based class must also derive from `ComponentBase`. Then, in the Razor component file, add the `@inherits` directive to specify the base class for the component (`@inherits CounterBase`).
+A Razor component is typically authored in a single *.razor* file. However, it's also possible to separate the code and markup using a code-behind file. To use a code-behind file, add a C# file that matches the file name of the component file but with a *.cs* extension added (*Counter.razor.cs*).
+
+The preferred approach is to declare the code-behind class as a `partial` class with the same name as the component. Because the Razor component file already generates a partial class with the same name, the two parts merge at compile time, and you don't need the `@inherits` directive.
+
+*Counter.razor*
+
+```razor
+<h1>Counter</h1>
+
+<p>Current count: @currentCount</p>
+
+<button @onclick="IncrementCount">Click me</button>
+```
+
+*Counter.razor.cs*
+
+```csharp
+public partial class Counter : ComponentBase
+{
+    private int currentCount = 0;
+
+    private void IncrementCount()
+    {
+        currentCount++;
+    }
+}
+```
+
+With the partial class approach, members don't need to be `protected` — `private` members are accessible because both parts of the partial class compile into the same class.
+
+Alternatively, you can use a base class. Define a base class that derives from `ComponentBase`, then add the `@inherits` directive in the Razor component file to specify the base class. It's common to name the base class after the component with a `Base` suffix (`CounterBase`).
 
 *Counter.razor*
 
@@ -691,7 +722,7 @@ public class CounterBase : ComponentBase
 }
 ```
 
-The visibility of the component's members in the base class must be `protected` or `public` to be visible to the component class.
+The visibility of members in the base class must be `protected` or `public` to be visible to the component class. Also, with the base class approach, the IDE may show both the component and its base class in IntelliSense lists. Use the partial class approach to avoid that duplication.
 
 ## Additional resources
 

From 1e1dd1bf633f97caa61f7efe116e70e6d1a1fda5 Mon Sep 17 00:00:00 2001
From: Bill Wagner <wiwagn@microsoft.com>
Date: Fri, 20 Mar 2026 10:15:54 -0400
Subject: [PATCH 3/3] Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 .../blazor-for-web-forms-developers/components.md             | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/docs/architecture/blazor-for-web-forms-developers/components.md b/docs/architecture/blazor-for-web-forms-developers/components.md
index 3e877b7879f3a..5b5af4c485299 100644
--- a/docs/architecture/blazor-for-web-forms-developers/components.md
+++ b/docs/architecture/blazor-for-web-forms-developers/components.md
@@ -681,7 +681,7 @@ The preferred approach is to declare the code-behind class as a `partial` class
 *Counter.razor.cs*
 
 ```csharp
-public partial class Counter : ComponentBase
+public partial class Counter
 {
     private int currentCount = 0;
 
@@ -692,7 +692,7 @@ public partial class Counter : ComponentBase
 }
 ```
 
-With the partial class approach, members don't need to be `protected` — `private` members are accessible because both parts of the partial class compile into the same class.
+With the partial class approach, members don't need to be `protected`. `private` members are accessible because both parts of the partial class compile into the same class.
 
 Alternatively, you can use a base class. Define a base class that derives from `ComponentBase`, then add the `@inherits` directive in the Razor component file to specify the base class. It's common to name the base class after the component with a `Base` suffix (`CounterBase`).