Add NotFoundPage to Router

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

@@ -1,6 +1,8 @@
 #nullable enable
 Microsoft.AspNetCore.Components.NavigationManager.NotFoundEvent -> System.EventHandler<System.EventArgs!>!
 virtual Microsoft.AspNetCore.Components.NavigationManager.NotFound() -> void
+Microsoft.AspNetCore.Components.Routing.Router.NotFoundPage.get -> System.Type!
+Microsoft.AspNetCore.Components.Routing.Router.NotFoundPage.set -> void
 Microsoft.AspNetCore.Components.Infrastructure.ComponentStatePersistenceManager.ComponentStatePersistenceManager(Microsoft.Extensions.Logging.ILogger<Microsoft.AspNetCore.Components.Infrastructure.ComponentStatePersistenceManager!>! logger, System.IServiceProvider! serviceProvider) -> void
 Microsoft.AspNetCore.Components.Infrastructure.ComponentStatePersistenceManager.SetPlatformRenderMode(Microsoft.AspNetCore.Components.IComponentRenderMode! renderMode) -> void
 Microsoft.AspNetCore.Components.Infrastructure.RegisterPersistentComponentStateServiceCollectionExtensions

src/Components/Components/src/Routing/Router.cs

@@ -3,11 +3,13 @@
 
 #nullable disable warnings
 
+using System.Diagnostics.CodeAnalysis;
 using System.Reflection;
 using System.Reflection.Metadata;
 using System.Runtime.ExceptionServices;
 using Microsoft.AspNetCore.Components.HotReload;
 using Microsoft.AspNetCore.Components.Rendering;
+using Microsoft.AspNetCore.Internal;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.DependencyInjection;
 
@@ -70,6 +72,13 @@ static readonly IReadOnlyDictionary<string, object> _emptyParametersDictionary
     [Parameter]
     public RenderFragment NotFound { get; set; }
 
+    /// <summary>
+    /// Gets or sets the page content to display when no match is found for the requested route.
+    /// </summary>
+    [Parameter]
+    [DynamicallyAccessedMembers(LinkerFlags.Component)]
+    public Type NotFoundPage { get; set; } = default!;
+
     /// <summary>
     /// Gets or sets the content to display when a match is found for the requested route.
     /// </summary>
@@ -132,6 +141,22 @@ public async Task SetParametersAsync(ParameterView parameters)
             throw new InvalidOperationException($"The {nameof(Router)} component requires a value for the parameter {nameof(Found)}.");
         }
 
+        if (NotFoundPage != null)
+        {
+            if (!typeof(IComponent).IsAssignableFrom(NotFoundPage))
+            {
+                throw new InvalidOperationException($"The type {NotFoundPage.FullName} " +
+                    $"does not implement {typeof(IComponent).FullName}.");
+            }
+
+            var routeAttributes = NotFoundPage.GetCustomAttributes(typeof(RouteAttribute), inherit: true);
+            if (routeAttributes.Length == 0)
+            {
+                throw new InvalidOperationException($"The type {NotFoundPage.FullName} " +
+                    $"does not have a {typeof(RouteAttribute).FullName} applied to it.");
+            }
+        }
+
         if (!_onNavigateCalled)
         {
             _onNavigateCalled = true;
@@ -327,7 +352,22 @@ private void OnNotFound(object sender, EventArgs args)
         if (_renderHandle.IsInitialized)
         {
             Log.DisplayingNotFound(_logger);
-            _renderHandle.Render(NotFound ?? DefaultNotFoundContent);
+            _renderHandle.Render(builder =>
+            {
+                if (NotFoundPage != null)
+                {
+                    builder.OpenComponent(0, NotFoundPage);
+                    builder.CloseComponent();
+                }
+                else if (NotFound != null)
+                {
+                    NotFound(builder);
+                }
+                else
+                {
+                    DefaultNotFoundContent(builder);
+                }
+            });
         }
     }
 

src/Components/test/E2ETest/Tests/GlobalInteractivityTest.cs

@@ -22,12 +22,16 @@ public class GlobalInteractivityTest(
 {
 
     [Theory]
-    [InlineData("server", true)]
-    [InlineData("webassembly", true)]
-    [InlineData("ssr", false)]
-    public void CanRenderNotFoundInteractive(string renderingMode, bool isInteractive)
+    [InlineData("server", true, false)]
+    [InlineData("webassembly", true, false)]
+    [InlineData("server", true, true)]
+    [InlineData("webassembly", true, true)]
+    [InlineData("ssr", false, true)]
+    [InlineData("ssr", false, false)]
+    public void CanRenderNotFoundPage(string renderingMode, bool isInteractive, bool useCustomNotFoundPage)
     {
-        Navigate($"/subdir/render-not-found-{renderingMode}");
+        string query = useCustomNotFoundPage ? "?useCustomNotFoundPage=true" : "";
+        Navigate($"{ServerPathBase}/render-not-found-{renderingMode}{query}");
 
         if (isInteractive)
         {
@@ -36,8 +40,16 @@ public void CanRenderNotFoundInteractive(string renderingMode, bool isInteractiv
             Browser.Exists(By.Id(buttonId)).Click();
         }
 
-        var bodyText = Browser.FindElement(By.TagName("body")).Text;
-        Assert.Contains("There's nothing here", bodyText);
+        if (useCustomNotFoundPage)
+        {
+            var infoText = Browser.FindElement(By.Id("test-info")).Text;
+            Assert.Contains("Welcome On Custom Not Found Page", infoText);
+        }
+        else
+        {
+            var bodyText = Browser.FindElement(By.TagName("body")).Text;
+            Assert.Contains("There's nothing here", bodyText);
+        }
     }
 
     [Fact]

src/Components/test/testassets/Components.WasmMinimal/Pages/CustomNotFoundPage.razor

@@ -0,0 +1,4 @@
+@page "/render-custom-not-found-page"
+
+<h3 id="test-info">Welcome On Custom Not Found Page</h3>
+<p>Sorry, the page you are looking for does not exist.</p>

src/Components/test/testassets/Components.WasmMinimal/Routes.razor

@@ -1,6 +1,28 @@
 @using Microsoft.AspNetCore.Components.Routing
+@using Components.WasmMinimal.Pages
+@inject NavigationManager NavigationManager
 
-<Router AppAssembly="@typeof(Program).Assembly">
+@code {
+    [Parameter]
+    [SupplyParameterFromQuery(Name = "useCustomNotFoundPage")]
+    public string? UseCustomNotFoundPage { get; set; }
+
+    private Type? NotFoundPageType { get; set; }
+
+    protected override void OnParametersSet()
+    {
+        if (UseCustomNotFoundPage == "true")
+        {
+            NotFoundPageType = typeof(CustomNotFoundPage);
+        }
+        else
+        {
+            NotFoundPageType = null;
+        }
+    }
+}
+
+<Router AppAssembly="@typeof(Program).Assembly" NotFoundPage="NotFoundPageType">
     <Found Context="routeData">
         <RouteView RouteData="@routeData" />
         <FocusOnNavigate RouteData="@routeData" Selector="h1" />

src/ProjectTemplates/Web.ProjectTemplates/content/BlazorWeb-CSharp/BlazorWeb-CSharp.Client/Pages/WeatherDetails.razor

@@ -0,0 +1,39 @@
+@page "/weather/details/{date}"
+@*#if (UseServer && !InteractiveAtRoot)
+@rendermode InteractiveAuto
+##elseif (!InteractiveAtRoot)
+@rendermode InteractiveWebAssembly
+##endif*@
+@inject NavigationManager NavigationManager
+
+@if (weatherDetails == null)
+{
+    <p><em>Loading...</em></p>
+}
+else
+{
+    <div>
+        <p><strong>Date:</strong> @weatherDetails.Date.ToShortDateString()</p>
+        <p><strong>Temperature (C):</strong> @weatherDetails.TemperatureC</p>
+        <p><strong>Temperature (F):</strong> @weatherDetails.TemperatureF</p>
+        <p><strong>Summary:</strong> @weatherDetails.Summary</p>
+    </div>
+}
+
+@code{
+    [Parameter]
+    public string? Date { get; set; }
+
+    private WeatherForecast? weatherDetails;
+
+    protected override async Task OnInitializedAsync()
+    {
+        weatherDetails = null;
+
+        // Simulate fetching data from a database
+        await Task.Delay(500);
+
+        // Simulate a scenario where the details are not found
+        NavigationManager.NotFound();
+    }
+}

src/ProjectTemplates/Web.ProjectTemplates/content/BlazorWeb-CSharp/BlazorWeb-CSharp/Components/Models/WeatherForecast.cs

@@ -0,0 +1,8 @@
+public class WeatherForecast
+{
+    public int Id { get; set; }
+    public DateOnly Date { get; set; }
+    public int TemperatureC { get; set; }
+    public string? Summary { get; set; }
+    public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
+}

src/ProjectTemplates/Web.ProjectTemplates/content/BlazorWeb-CSharp/BlazorWeb-CSharp/Components/Pages/NotFound.razor

@@ -0,0 +1,4 @@
+@page "/not-found"
+
+<h3>Not Found</h3>
+<p>Sorry, the content you are looking for does not exist.</p>

src/ProjectTemplates/Web.ProjectTemplates/content/BlazorWeb-CSharp/BlazorWeb-CSharp/Components/Pages/Weather.razor

@@ -1,6 +1,8 @@
 @page "/weather"
 @*#if (!InteractiveAtRoot) -->
 @attribute [StreamRendering]
+##else
+@inject NavigationManager NavigationManager
 ##endif*@
 
 <PageTitle>Weather</PageTitle>
@@ -32,6 +34,13 @@ else
                     <td>@forecast.TemperatureC</td>
                     <td>@forecast.TemperatureF</td>
                     <td>@forecast.Summary</td>
+                    <td>
+@*#if (InteractiveAtRoot) -->
+                        <button class="btn btn-primary" @onclick="() => NavigateToDetails(forecast.Id)">More info</button>
+##else
+                        <a href="@($"/weather/details/{forecast.Id}")">More info</a>
+##endif*@
+                    </td>
                 </tr>
             }
         </tbody>
@@ -54,17 +63,17 @@ else
         var summaries = new[] { "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching" };
         forecasts = Enumerable.Range(1, 5).Select(index => new WeatherForecast
         {
+            Id = index,
             Date = startDate.AddDays(index),
             TemperatureC = Random.Shared.Next(-20, 55),
             Summary = summaries[Random.Shared.Next(summaries.Length)]
         }).ToArray();
     }
 
-    private class WeatherForecast
+@*#if (InteractiveAtRoot) -->
+    private void NavigateToDetails(int id)
     {
-        public DateOnly Date { get; set; }
-        public int TemperatureC { get; set; }
-        public string? Summary { get; set; }
-        public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
+        NavigationManager.NavigateTo($"/weather/details/{id}");
     }
+##endif*@
 }

src/ProjectTemplates/Web.ProjectTemplates/content/BlazorWeb-CSharp/BlazorWeb-CSharp/Components/Pages/WeatherDetails.razor

@@ -0,0 +1,37 @@
+@page "/weather/details/{id:int}"
+@*#if (!InteractiveAtRoot) -->
+@attribute [StreamRendering]
+##endif*@
+@inject NavigationManager NavigationManager
+
+@if (weatherDetails == null)
+{
+    <p><em>Loading...</em></p>
+}
+else
+{
+    <div>
+        <p><strong>Date:</strong> @weatherDetails.Date.ToShortDateString()</p>
+        <p><strong>Temperature (C):</strong> @weatherDetails.TemperatureC</p>
+        <p><strong>Temperature (F):</strong> @weatherDetails.TemperatureF</p>
+        <p><strong>Summary:</strong> @weatherDetails.Summary</p>
+    </div>
+}
+
+@code{
+    [Parameter]
+    public int Id { get; set; }
+
+    private WeatherForecast? weatherDetails;
+
+    protected override async Task OnInitializedAsync()
+    {
+        weatherDetails = null;
+
+        // Simulate fetching data from a database
+        await Task.Delay(500);
+
+        // Simulate a scenario where the details are not found
+        NavigationManager.NotFound();
+    }
+}

src/ProjectTemplates/Web.ProjectTemplates/content/BlazorWeb-CSharp/BlazorWeb-CSharp/Components/Routes.razor

@@ -2,9 +2,9 @@
 @using BlazorWeb_CSharp.Components.Account.Shared
 ##endif*@
 @*#if (UseWebAssembly && !InteractiveAtRoot)
-<Router AppAssembly="typeof(Program).Assembly" AdditionalAssemblies="new[] { typeof(Client._Imports).Assembly }">
+<Router AppAssembly="typeof(Program).Assembly" AdditionalAssemblies="new[] { typeof(Client._Imports).Assembly }" NotFoundPage="typeof(Pages.NotFound)">
 ##else
-<Router AppAssembly="typeof(Program).Assembly">
+<Router AppAssembly="typeof(Program).Assembly" NotFoundPage="typeof(Pages.NotFound)">
 ##endif*@
     <Found Context="routeData">
         @*#if (IndividualLocalAuth)

src/ProjectTemplates/scripts/startvs.cmd

@@ -0,0 +1,34 @@
+@ECHO OFF
+SETLOCAL
+
+:: This command launches a Visual Studio solution with environment variables required to use a local version of the .NET Core SDK.
+
+:: This tells .NET Core to use the same dotnet.exe that build scripts use
+SET DOTNET_ROOT=%~dp0\.dotnet
+SET DOTNET_ROOT(x86)=%~dp0\.dotnet\x86
+
+:: This tells .NET Core not to go looking for .NET Core in other places
+SET DOTNET_MULTILEVEL_LOOKUP=0
+
+:: Put our local dotnet.exe on PATH first so Visual Studio knows which one to use
+SET PATH=%DOTNET_ROOT%;%PATH%
+
+SET sln=%~1
+
+IF "%sln%"=="" (
+    echo Error^: Expected argument ^<SLN_FILE^>
+    echo Usage^: startvs.cmd ^<SLN_FILE^>
+
+    exit /b 1
+)
+
+IF NOT EXIST "%DOTNET_ROOT%\dotnet.exe" (
+    echo .NET Core has not yet been installed. Run `%~dp0restore.cmd` to install tools
+    exit /b 1
+)
+
+IF "%VSINSTALLDIR%" == "" (
+    start "" "%sln%"
+) else (
+    "%VSINSTALLDIR%\Common7\IDE\devenv.com" "%sln%"
+)