Cascading values updates (#31488)

Author: guardrex

aspnetcore/blazor/components/cascading-values-and-parameters.md

@@ -33,7 +33,7 @@ The following class is used in this section's examples.
 
 :::code language="csharp" source="~/../blazor-samples/8.0/BlazorSample_BlazorWebApp/Dalek.cs":::
 
-The following registrations are made in the app's `Program` file:
+The following registrations are made in the app's `Program` file with <xref:Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.AddCascadingValue%2A>:
 
 * `Dalek` with a property value for `Units` is registered as a fixed cascading value.
 * A second `Dalek` registration with a different property value for `Units` is named "`AlphaGroup`".
@@ -60,6 +60,13 @@ builder.Services.AddCascadingValue(sp =>
 });
 ```
 
+> [!WARNING]
+> Registering a component type as a root-level cascading value doesn't register additional services for the type or permit service activation in the component.
+>
+> Treat required services separately from cascading values, registering them separately from the cascaded type.
+>
+> Avoid using <xref:Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.AddCascadingValue%2A> to register a component type as a cascading value. Instead, wrap the `<Router>...</Router>` in the `Routes` component (`Components/Routes.razor`) with the component and adopt global interactive server-side rendering (interactive SSR). For an example, see the [`CascadingValue` component](#cascadingvalue-component) section.
+
 :::moniker-end
 
 ## `CascadingValue` component
@@ -468,3 +475,8 @@ The following `ExampleTabSet` component uses the `TabSet` component, which conta
     private bool showThirdTab;
 }
 ```
+
+## Additional resources
+
+* [Generic type support: Explicit generic types based on ancestor components](xref:blazor/components/generic-type-support#explicit-generic-types-based-on-ancestor-components)
+* [State management: Factor out the state preservation to a common location](xref:blazor/state-management?pivots=server#factor-out-the-state-preservation-to-a-common-location)

aspnetcore/blazor/state-management.md

@@ -493,8 +493,26 @@ else
 
 The `CounterStateProvider` component handles the loading phase by not rendering its child content until state loading is complete.
 
+:::moniker range=">= aspnetcore-8.0"
+
+To make the state accessible to all components in an app, wrap the `CounterStateProvider` component around the <xref:Microsoft.AspNetCore.Components.Routing.Router> (`<Router>...</Router>`) in the `Routes` component with global interactive server-side rendering (interactive SSR).
+
+In the `App` component (`Components/App.razor`):
+
+```razor
+<Routes @rendermode="InteractiveServer" />
+```
+
+In the `Routes` component (`Components/Routes.razor`):
+
+:::moniker-end
+
+:::moniker range="< aspnetcore-8.0"
+
 To use the `CounterStateProvider` component, wrap an instance of the component around any other component that requires access to the counter state. To make the state accessible to all components in an app, wrap the `CounterStateProvider` component around the <xref:Microsoft.AspNetCore.Components.Routing.Router> in the `App` component (`App.razor`):
 
+:::moniker-end
+
 ```razor
 <CounterStateProvider>
     <Router ...>
@@ -773,8 +791,6 @@ When implementing custom state storage, a useful approach is to adopt [cascading
 * To consume state across many components.
 * If there's just one top-level state object to persist.
 
-For additional discussion and example approaches, see [Blazor: In-memory state container as cascading parameter (dotnet/AspNetCore.Docs #27296)](https://github.com/dotnet/AspNetCore.Docs/issues/27296).
-
 ## Troubleshoot
 
 In a custom state management service, a callback invoked outside of Blazor's synchronization context must wrap the logic of the callback in <xref:Microsoft.AspNetCore.Components.ComponentBase.InvokeAsync%2A?displayProperty=nameWithType> to move it onto the renderer's synchronization context.