Blazor Hybrid routing and nav topic

aspnetcore/blazor/hybrid/routing.md

@@ -0,0 +1,75 @@
+---
+title: ASP.NET Core Blazor Hybrid routing and navigation
+author: guardrex
+description: Learn how to manage request routing and navigation in Blazor Hybrid apps.
+monikerRange: '>= aspnetcore-6.0'
+ms.author: riande
+ms.custom: "mvc"
+ms.date: 02/24/2022
+no-loc: ["Blazor Hybrid", Home, Privacy, Kestrel, appsettings.json, "ASP.NET Core Identity", cookie, Cookie, Blazor, "Blazor Server", "Blazor WebAssembly", "Identity", "Let's Encrypt", Razor, SignalR]
+uid: blazor/hybrid/routing
+---
+# ASP.NET Core Blazor Hybrid routing and navigation
+
+[!INCLUDE[](~/blazor/includes/blazor-hybrid-preview-notice.md)]
+
+Register to the `ExternalNavigationStarting` event and set the `ExternalLinkNavigationEventArgs.ExternalLinkNavigationPolicy` property to change link handling behavior. The `ExternalLinkNavigationPolicy` enumeration (`enum`) allows setting link handling behavior to `OpenInExternalBrowser`, `InsecureOpenInWebView`, and `CancelNavigation`. The `ExternalLinkNavigationEventArgs.Uri` property can be used to dynamically set link handling behavior.
+
+> [!WARNING]
+> External links are opened in the device's default browser by default. Opening external links within a `BlazorWebView` can introduce security vulnerabilities and should ***not*** be enabled unless you can ensure that the external links are fully trusted.
+
+## .NET MAUI
+
+For the `Page` with the `BlazorWebView`:
+
+* Add the `Microsoft.AspNetCore.Components.WebView` namespace:
+
+  ```csharp
+  using Microsoft.AspNetCore.Components.WebView;
+  ```
+
+* Add the following event handler to the constructor:
+
+  ```csharp
+  blazorWebView.ExternalNavigationStarting += 
+      (sender, externalLinkNavigationEventArgs) =>
+      {
+          externalLinkNavigationEventArgs.ExternalLinkNavigationPolicy = 
+              ExternalLinkNavigationPolicy.InsecureOpenInWebView;
+      };
+  ```
+
+## WPF
+
+Add the `ExternalNavigationStarting="Handle_ExternalNavigationStarting"` attribute to the `BlazorWebView` control in the `.xaml` file:
+
+```xaml
+<blazor:BlazorWebView HostPage="wwwroot\index.html" 
+    Services="{StaticResource services}" 
+    x:Name="blazorWebView" 
+    ExternalNavigationStarting="Handle_ExternalNavigationStarting" >
+```
+
+Add the event handler in the `.xaml.cs` file:
+
+```csharp
+private void Handle_ExternalNavigationStarting(
+    object sender, ExternalLinkNavigationEventArgs externalLinkNavigationEventArgs)
+{
+    externalLinkNavigationEventArgs.ExternalLinkNavigationPolicy = 
+        ExternalLinkNavigationPolicy.InsecureOpenInWebView;
+}
+```
+
+## Winforms
+
+In the constructor of the form containing the `BlazorWebView` control, add the following event registration:
+
+```csharp
+blazorWebView.ExternalNavigationStarting += 
+    (sender, externalLinkNavigationEventArgs) =>
+    {
+        externalLinkNavigationEventArgs.ExternalLinkNavigationPolicy = 
+            ExternalLinkNavigationPolicy.InsecureOpenInWebView;
+    };
+```

aspnetcore/toc.yml

@@ -349,6 +349,8 @@ items:
                     uid: blazor/hybrid/tutorials/windows-forms
                   - name: WPF
                     uid: blazor/hybrid/tutorials/wpf
+              - name: Routing and navigation
+                uid: blazor/hybrid/routing
           - name: Project structure
             uid: blazor/project-structure
           - name: Fundamentals