HttpNavigationManager no longer uses NavigationException

src/Components/Components/src/NavigationManager.cs

@@ -61,6 +61,18 @@ public event EventHandler<NotFoundEventArgs> OnNotFound
     // The URI. Always represented an absolute URI.
     private string? _uri;
     private bool _isInitialized;
+    private const string EnableThrowNavigationException = "Microsoft.AspNetCore.Components.Endpoints.HttpNavigationManager.EnableThrowNavigationException";
+
+    /// <summary>
+    /// Gets a value indicating whether navigation exceptions should be thrown during navigation.
+    /// </summary>
+    /// <remarks>
+    /// This property is controlled by the AppContext switch
+    /// <c>Microsoft.AspNetCore.Components.Endpoints.HttpNavigationManager.EnableThrowNavigationException</c>.
+    /// When enabled, navigation operations may throw exceptions for debugging or testing purposes.
+    /// </remarks>
+    protected static bool ThrowNavigationException =>
+        AppContext.TryGetSwitch(EnableThrowNavigationException, out var switchValue) && switchValue;
 
     /// <summary>
     /// Gets or sets the current base URI. The <see cref="BaseUri" /> is always represented as an absolute URI in string form with trailing slash.

src/Components/Components/src/PublicAPI.Unshipped.txt

@@ -11,3 +11,8 @@ Microsoft.AspNetCore.Components.SupplyParameterFromPersistentComponentStateAttri
 Microsoft.Extensions.DependencyInjection.SupplyParameterFromPersistentComponentStateProviderServiceCollectionExtensions
 static Microsoft.AspNetCore.Components.Infrastructure.RegisterPersistentComponentStateServiceCollectionExtensions.AddPersistentServiceRegistration<TService>(Microsoft.Extensions.DependencyInjection.IServiceCollection! services, Microsoft.AspNetCore.Components.IComponentRenderMode! componentRenderMode) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
 static Microsoft.Extensions.DependencyInjection.SupplyParameterFromPersistentComponentStateProviderServiceCollectionExtensions.AddSupplyValueFromPersistentComponentStateProvider(this Microsoft.Extensions.DependencyInjection.IServiceCollection! services) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
+static Microsoft.AspNetCore.Components.NavigationManager.ThrowNavigationException.get -> bool
+Microsoft.AspNetCore.Components.Routing.NavigationEventArgs
+Microsoft.AspNetCore.Components.Routing.NavigationEventArgs.Uri.get -> string!
+Microsoft.AspNetCore.Components.Routing.NavigationEventArgs.NavigationEventArgs(string! uri) -> void
+Microsoft.AspNetCore.Components.Routing.IHostEnvironmentNavigationManager.OnNavigateTo -> System.EventHandler<Microsoft.AspNetCore.Components.Routing.NavigationEventArgs!>!

src/Components/Components/src/Routing/IHostEnvironmentNavigationManager.cs

@@ -15,4 +15,12 @@ public interface IHostEnvironmentNavigationManager
     /// <param name="baseUri">The base URI.</param>
     /// <param name="uri">The absolute URI.</param>
     void Initialize(string baseUri, string uri);
+
+    /// <summary>
+    /// An event that is triggered when SSR navigation occurs.
+    /// </summary>
+    /// <remarks>
+    /// This event allows subscribers to respond to SSR navigation actions, such as updating state or performing side effects.
+    /// </remarks>
+    event EventHandler<NavigationEventArgs> OnNavigateTo;
 }

src/Components/Components/src/Routing/NavigationEventArgs.cs

@@ -0,0 +1,24 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Components.Routing;
+
+/// <summary>
+/// <see cref="EventArgs" /> for <see cref="NavigationManager.LocationChanged" />.
+/// </summary>
+public class NavigationEventArgs : EventArgs
+{
+    /// <summary>
+    /// Gets the URI of the navigation event.
+    /// </summary>
+    public string Uri { get; }
+
+    /// <summary>
+    /// Initializes a new instance of <see cref="NavigationEventArgs"/>.
+    /// </summary>
+    /// <param name="uri">The URI of the navigation event.</param>
+    public NavigationEventArgs(string uri)
+    {
+        Uri = uri;
+    }
+}

src/Components/Endpoints/src/DependencyInjection/HttpNavigationManager.cs

@@ -7,11 +7,25 @@ namespace Microsoft.AspNetCore.Components.Endpoints;
 
 internal sealed class HttpNavigationManager : NavigationManager, IHostEnvironmentNavigationManager
 {
+    private EventHandler<NavigationEventArgs>? _onNavigateTo;
+    public event EventHandler<NavigationEventArgs> OnNavigateTo
+    {
+        add => _onNavigateTo += value;
+        remove => _onNavigateTo -= value;
+    }
+
     void IHostEnvironmentNavigationManager.Initialize(string baseUri, string uri) => Initialize(baseUri, uri);
 
     protected override void NavigateToCore(string uri, NavigationOptions options)
     {
         var absoluteUriString = ToAbsoluteUri(uri).AbsoluteUri;
-        throw new NavigationException(absoluteUriString);
+        if (ThrowNavigationException)
+        {
+            throw new NavigationException(absoluteUriString);
+        }
+        else
+        {
+            _onNavigateTo?.Invoke(this, new NavigationEventArgs(absoluteUriString));
+        }
     }
 }

src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.cs

@@ -84,6 +84,10 @@ internal async Task InitializeStandardComponentServicesAsync(
         if (navigationManager != null)
         {
             navigationManager.OnNotFound += SetNotFoundResponse;
+            if (navigationManager is IHostEnvironmentNavigationManager hostEnvironmentNavigationManager)
+            {
+                hostEnvironmentNavigationManager.OnNavigateTo += OnNavigateTo;
+            }
         }
 
         var authenticationStateProvider = httpContext.RequestServices.GetService<AuthenticationStateProvider>();
@@ -135,6 +139,11 @@ internal async Task InitializeStandardComponentServicesAsync(
         }
     }
 
+    private void OnNavigateTo(object? sender, NavigationEventArgs args)
+    {
+        _httpContext.Response.Redirect(args.Uri);
+    }
+
     private static void InitializeResourceCollection(HttpContext httpContext)
     {
 

src/Components/Endpoints/test/RazorComponentResultTest.cs

@@ -510,6 +510,14 @@ class FakeDataProtector : IDataProtector
 
     class FakeNavigationManager : NavigationManager, IHostEnvironmentNavigationManager
     {
+        private EventHandler<NavigationEventArgs> _onNavigateTo;
+
+        public event EventHandler<NavigationEventArgs> OnNavigateTo
+        {
+            add => _onNavigateTo += value;
+            remove => _onNavigateTo -= value;
+        }
+
         public new void Initialize(string baseUri, string uri)
             => base.Initialize(baseUri, uri);
 

src/Components/Server/src/Circuits/RemoteNavigationManager.cs

@@ -17,6 +17,12 @@ internal sealed partial class RemoteNavigationManager : NavigationManager, IHost
     private readonly ILogger<RemoteNavigationManager> _logger;
     private IJSRuntime _jsRuntime;
     private bool? _navigationLockStateBeforeJsRuntimeAttached;
+    private EventHandler<NavigationEventArgs>? _onNavigateTo;
+    public event EventHandler<NavigationEventArgs> OnNavigateTo
+    {
+        add => _onNavigateTo += value;
+        remove => _onNavigateTo -= value;
+    }
 
     public event EventHandler<Exception>? UnhandledException;
 
@@ -88,7 +94,14 @@ protected override void NavigateToCore(string uri, NavigationOptions options)
         if (_jsRuntime == null)
         {
             var absoluteUriString = ToAbsoluteUri(uri).AbsoluteUri;
-            throw new NavigationException(absoluteUriString);
+            if (ThrowNavigationException)
+            {
+                throw new NavigationException(absoluteUriString);
+            }
+            else
+            {
+                _onNavigateTo?.Invoke(this, new NavigationEventArgs(absoluteUriString));
+            }
         }
 
         _ = PerformNavigationAsync();
@@ -129,7 +142,14 @@ public override void Refresh(bool forceReload = false)
         if (_jsRuntime == null)
         {
             var absoluteUriString = ToAbsoluteUri(Uri).AbsoluteUri;
-            throw new NavigationException(absoluteUriString);
+            if (ThrowNavigationException)
+            {
+                throw new NavigationException(absoluteUriString);
+            }
+            else
+            {
+                _onNavigateTo?.Invoke(this, new NavigationEventArgs(absoluteUriString));
+            }
         }
 
         _ = RefreshAsync();

src/Components/test/E2ETest/ServerRenderingTests/InteractivityTest.cs

@@ -1399,4 +1399,16 @@ public void CanPersistMultiplePrerenderedStateDeclaratively_Auto_PersistsOnWebAs
         Browser.Equal("restored 2", () => Browser.FindElement(By.Id("auto-2")).Text);
         Browser.Equal("WebAssembly", () => Browser.FindElement(By.Id("render-mode-auto-2")).Text);
     }
+
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void NavigatesWithInteractivityByRequestRedirection(bool controlFlowByException)
+    {
+        AppContext.SetSwitch("Microsoft.AspNetCore.Components.Endpoints.EnableThrowNavigationException", isEnabled: controlFlowByException);
+        Navigate($"{ServerPathBase}/routing/ssr-navigate-to");
+        Browser.Equal("Click submit to navigate to home", () => Browser.Exists(By.Id("test-info")).Text);
+        Browser.Click(By.Id("redirectButton"));
+        Browser.Equal("Routing test cases", () => Browser.Exists(By.Id("test-info")).Text);
+    }
 }

src/Components/test/E2ETest/ServerRenderingTests/NoInteractivityTest.cs

@@ -64,4 +64,16 @@ public void CanUseServerAuthenticationStateByDefault()
         Browser.Equal("True", () => Browser.FindElement(By.Id("is-in-test-role-1")).Text);
         Browser.Equal("True", () => Browser.FindElement(By.Id("is-in-test-role-2")).Text);
     }
+
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public void NavigatesWithoutInteractivityByRequestRedirection(bool controlFlowByException)
+    {
+        AppContext.SetSwitch("Microsoft.AspNetCore.Components.Endpoints.EnableThrowNavigationException", isEnabled: controlFlowByException);
+        Navigate($"{ServerPathBase}/routing/ssr-navigate-to");
+        Browser.Equal("Click submit to navigate to home", () => Browser.Exists(By.Id("test-info")).Text);
+        Browser.Click(By.Id("redirectButton"));
+        Browser.Equal("Routing test cases", () => Browser.Exists(By.Id("test-info")).Text);
+    }
 }

src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Routing/RoutingTestCases.razor

@@ -1,5 +1,5 @@
 @page "/routing"
-<h3>Routing test cases</h3>
+<h3 id="test-info">Routing test cases</h3>
 
 <ul>
     <li>
@@ -24,12 +24,6 @@
         <a href="routing/complex-segment(value)">Complex segments</a>
     </li>
     <li>
-        <a href="routing/not-found-ssr">Not found page for Static Server Rendering</a>
-    </li>
-    <li>
-        <a href="routing/not-found-webassembly">Not found page for Interactive WebAssembly rendering</a>
-    </li>
-    <li>
-        <a href="routing/not-found-server">Not found page for Interactive Server rendering</a>
+        <a href="routing/ssr-navigate-to">Redirect on SSR page</a>
     </li>
 </ul>

src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Routing/SSRRedirection.razor

@@ -0,0 +1,17 @@
+@page "/routing/ssr-navigate-to"
+@using Microsoft.AspNetCore.Components.Forms
+@inject NavigationManager NavigationManager
+
+<p id="test-info">Click submit to navigate to home</p>
+<form method="post" @onsubmit="Submit" @formname="MyUniqueFormName">
+    <AntiforgeryToken />
+    <button type="submit" id="redirectButton" class="btn btn-primary">Redirect</button>
+</form>
+
+@code {
+    private void Submit()
+    {
+        NavigationManager.NavigateTo("/subdir/routing");
+    }
+}
+

src/Mvc/Mvc.TagHelpers/test/ComponentTagHelperTest.cs

@@ -104,6 +104,14 @@ protected override void BuildRenderTree(RenderTreeBuilder builder)
 
     class MockNavigationManager : NavigationManager, IHostEnvironmentNavigationManager
     {
+        private EventHandler<NavigationEventArgs> _onNavigateTo;
+
+        public event EventHandler<NavigationEventArgs> OnNavigateTo
+        {
+            add => _onNavigateTo += value;
+            remove => _onNavigateTo -= value;
+        }
+
         public MockNavigationManager()
         {
            Initialize("https://localhost:85/subdir/", "https://localhost:85/subdir/path?query=value#hash");