[Blazor] rendering - event callbacks change detection (#35493)

Author: hakenr

aspnetcore/blazor/performance/rendering.md

@@ -28,11 +28,15 @@ The last two steps of the preceding sequence continue recursively down the compo
 
 To prevent rendering recursion into a particular subtree, use either of the following approaches:
 
-* Ensure that child component parameters are of primitive immutable types, such as `string`, `int`, `bool`, `DateTime`, and other similar types. The built-in logic for detecting changes automatically skips rerendering if the primitive immutable parameter values haven't changed. If you render a child component with `<Customer CustomerId="item.CustomerId" />`, where `CustomerId` is an `int` type, then the `Customer` component isn't rerendered unless `item.CustomerId` changes.
-* Override <xref:Microsoft.AspNetCore.Components.ComponentBase.ShouldRender%2A>:
-  * To accept nonprimitive parameter values, such as complex custom model types, event callbacks, or <xref:Microsoft.AspNetCore.Components.RenderFragment> values.
+* Ensure that child component parameters are of specific immutable types&dagger;, such as `string`, `int`, `bool`, and `DateTime`. The built-in logic for detecting changes automatically skips rerendering if the immutable parameter values haven't changed. If you render a child component with `<Customer CustomerId="item.CustomerId" />`, where `CustomerId` is an `int` type, then the `Customer` component isn't rerendered unless `item.CustomerId` changes.
+* Override [`ShouldRender`](xref:blazor/components/rendering#suppress-ui-refreshing-shouldrender), setting it to `false`:
+  * When parameters are nonprimitive types or unsupported immutable types&dagger;, such as complex custom model types or <xref:Microsoft.AspNetCore.Components.RenderFragment> values.
   * If authoring a UI-only component that doesn't change after the initial render, regardless of parameter value changes.
 
+&dagger;For more information, see [the change detection logic in Blazor's reference source (`ChangeDetection.cs`)](https://github.com/dotnet/aspnetcore/blob/main/src/Components/Components/src/ChangeDetection.cs).
+
+[!INCLUDE[](~/includes/aspnetcore-repo-ref-source-links.md)]
+
 The following airline flight search tool example uses private fields to track the necessary information to detect changes. The previous inbound flight identifier (`prevInboundFlightId`) and previous outbound flight identifier (`prevOutboundFlightId`) track information for the next potential component update. If either of the flight identifiers change when the component's parameters are set in [`OnParametersSet`](xref:blazor/components/lifecycle#after-parameters-are-set-onparameterssetasync), the component is rerendered because `shouldRender` is set to `true`. If `shouldRender` evaluates to `false` after checking the flight identifiers, an expensive rerender is avoided:
 
 ```razor