Access modifiers for cascading params (#36362)

Author: guardrex

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

@@ -241,7 +241,7 @@ The following component is used to demonstrate how changing the value of `Notify
     private int dalekCount;
 
     [CascadingParameter]
-    public NotifyingDalek? Dalek { get; set; }
+    private NotifyingDalek? Dalek { get; set; }
 
     private void Update()
     {
@@ -433,6 +433,8 @@ For more information, see the following sections of this article:
 
 To make use of cascading values, descendent components declare cascading parameters using the [`[CascadingParameter]` attribute](xref:Microsoft.AspNetCore.Components.CascadingParameterAttribute). Cascading values are bound to cascading parameters **by type**. Cascading multiple values of the same type is covered in the [Cascade multiple values](#cascade-multiple-values) section later in this article.
 
+The `private` access modifier is recommended for cascading parameters because the parameter should be scoped for use only within the component's class in most cases. When subclassing is required, use the `protected` access modifier.
+
 The following component binds the `ThemeInfo` cascading value to a cascading parameter, optionally using the same name of `ThemeInfo`. The parameter is used to set the CSS class for the **`Increment Counter (Themed)`** button.
 
 `ThemedCounter.razor`:
@@ -657,7 +659,7 @@ Descendent `Tab` components capture the containing `TabSet` as a cascading param
 
 @code {
     [CascadingParameter]
-    public TabSet? ContainerTabSet { get; set; }
+    private TabSet? ContainerTabSet { get; set; }
 
     [Parameter]
     public string? Title { get; set; }

aspnetcore/blazor/components/class-libraries-and-static-server-side-rendering.md

@@ -125,7 +125,7 @@ Reusable components are free to receive an <xref:Microsoft.AspNetCore.Http.HttpC
 
 ```csharp
 [CascadingParameter]
-public HttpContext? Context { get; set; }
+private HttpContext? Context { get; set; }
 ```
 
 The value is `null` during interactive rendering and is only set during static SSR.

aspnetcore/blazor/components/httpcontext.md

@@ -22,7 +22,7 @@ uid: blazor/components/httpcontext
 
 ```csharp
 [CascadingParameter]
-public HttpContext? HttpContext { get; set; }
+private HttpContext? HttpContext { get; set; }
 ```
 
 For additional context in *advanced* edge cases†, see the discussion in the following articles:

aspnetcore/blazor/fundamentals/handle-errors.md

@@ -596,7 +596,7 @@ To process errors in a component:
 
   ```csharp
   [CascadingParameter]
-  public ProcessError? ProcessError { get; set; }
+  private ProcessError? ProcessError { get; set; }
   ```
 
 * Call an error processing method in any `catch` block with an appropriate exception type. The example `ProcessError` component only offers a single `LogError` method, but the error processing component can provide any number of error processing methods to address alternative error processing requirements throughout the app. The following `Counter` component `@code` block example includes the `ProcessError` cascading parameter and traps an exception for logging when the count is greater than five:
@@ -606,7 +606,7 @@ To process errors in a component:
       private int currentCount = 0;
 
       [CascadingParameter]
-      public ProcessError? ProcessError { get; set; }
+      private ProcessError? ProcessError { get; set; }
 
       private void IncrementCount()
       {
@@ -689,7 +689,7 @@ To process errors in a component:
 
   ```razor
   [CascadingParameter]
-  public ProcessError ProcessError { get; set; }
+  private ProcessError ProcessError { get; set; }
   ```
 
 * Call an error processing method in any `catch` block with an appropriate exception type. The example `ProcessError` component only offers a single `LogError` method, but the error processing component can provide any number of error processing methods to address alternative error processing requirements throughout the app.

aspnetcore/blazor/fundamentals/routing.md

@@ -835,7 +835,7 @@ Apps that implement a custom router can also use `NavigationManager.NotFound`. T
   ```razor
   @code {
       [CascadingParameter]
-      public HttpContext? HttpContext { get; set; }
+      private HttpContext? HttpContext { get; set; }
 
       private void OnNotFoundEvent(object sender, NotFoundEventArgs e)
       {

aspnetcore/blazor/globalization-localization.md

@@ -760,7 +760,7 @@ Add the following `@code` block to the bottom of the `App` component file:
 ```razor
 @code {
     [CascadingParameter]
-    public HttpContext? HttpContext { get; set; }
+    private HttpContext? HttpContext { get; set; }
 
     protected override void OnInitialized()
     {
@@ -1350,7 +1350,7 @@ Add the following `@code` block to the bottom of the `App` component file:
 ```razor
 @code {
     [CascadingParameter]
-    public HttpContext? HttpContext { get; set; }
+    private HttpContext? HttpContext { get; set; }
 
     protected override void OnInitialized()
     {

aspnetcore/blazor/hybrid/root-component-parameters.md

@@ -230,7 +230,7 @@ The following `Keypad` component example:
 
 @code {
     [CascadingParameter]
-    protected KeypadViewModel KeypadViewModel { get; set; }
+    private KeypadViewModel KeypadViewModel { get; set; }
 
     private void DeleteChar()
     {

aspnetcore/blazor/security/content-security-policy.md

@@ -459,7 +459,7 @@ The rendered import map from the `ImportMap` component is generated by the app a
     private string? integrity;
 
     [CascadingParameter]
-    public HttpContext? HttpContext { get; set; }
+    private HttpContext? HttpContext { get; set; }
 
     protected override void OnInitialized()
     {