Enforce Snackbar usage only in packaged Windows apps

samples/CommunityToolkit.Maui.Sample/CommunityToolkit.Maui.Sample.csproj

@@ -59,7 +59,7 @@
     <!-- Custom Fonts -->
     <MauiFont Include="Resources\Fonts\*" />
 
-    <PackageReference Include="Microsoft.Maui.Controls" Version="*" />
+    <PackageReference Include="Microsoft.Maui.Controls" Version="$(MauiPackageVersion)" />
     <PackageReference Include="CommunityToolkit.Maui.Markup" Version="7.0.1" />
     <PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.2" />
     <PackageReference Include="Microsoft.Extensions.Http.Resilience" Version="10.5.0" />

src/CommunityToolkit.Maui/Alerts/Snackbar/Snackbar.shared.cs

@@ -1,4 +1,5 @@
 using CommunityToolkit.Maui.Core;
+using CommunityToolkit.Maui.Extensions;
 
 namespace CommunityToolkit.Maui.Alerts;
 
@@ -34,13 +35,19 @@ public partial class Snackbar : ISnackbar
 
 	bool isDisposed;
 	WeakReference<IView>? weakView;
-
 	/// <summary>
 	/// Initializes a new instance of <see cref="Snackbar"/>
 	/// </summary>
 	public Snackbar()
 	{
 #if WINDOWS
+		if (!AppPackageExtensions.IsPackagedApp)
+		{
+			throw new InvalidOperationException($"{nameof(Snackbar)} is not supported on unpackaged Windows apps. {nameof(Snackbar)} requires the app to be packaged (MSIX) because it uses the Windows App SDK AppNotificationManager API. See https://learn.microsoft.com/dotnet/communitytoolkit/maui/alerts/snackbar for more information.")
+			{
+				HelpLink = "https://learn.microsoft.com/dotnet/communitytoolkit/maui/alerts/snackbar"
+			};
+		}
 		if (!Options.ShouldEnableSnackbarOnWindows)
 		{
 			throw new InvalidOperationException($"Additional setup is required in the Package.appxmanifest file to enable {nameof(Snackbar)} on Windows. Additonally, `{nameof(AppBuilderExtensions.UseMauiCommunityToolkit)}(options => options.{nameof(Options.SetShouldEnableSnackbarOnWindows)}({bool.TrueString.ToLower()});` must be called to enable Snackbar on Windows. See the Platform Specific Initialization section of the {nameof(Snackbar)} documentaion for more information: https://learn.microsoft.com/dotnet/communitytoolkit/maui/alerts/snackbar")
@@ -166,6 +173,7 @@ public void Dispose()
 
 	internal static TimeSpan GetDefaultTimeSpan() => TimeSpan.FromSeconds(3);
 
+
 	void OnShown()
 	{
 		IsShown = true;
@@ -177,4 +185,4 @@ void OnDismissed()
 		IsShown = false;
 		weakEventManager.HandleEvent(this, EventArgs.Empty, nameof(Dismissed));
 	}
-}
+}

src/CommunityToolkit.Maui/Extensions/AppPackageExtensions.windows.cs

@@ -0,0 +1,43 @@
+using Windows.ApplicationModel;
+
+namespace CommunityToolkit.Maui.Extensions;
+
+// Since MediaElement can't access .NET MAUI internals we have to copy this code here
+// https://github.com/dotnet/maui/blob/main/src/Essentials/src/AppInfo/AppInfo.uwp.cs
+static class AppPackageExtensions
+{
+	static readonly Lazy<bool> isPackagedAppHolder = new(() =>
+	{
+		try
+		{
+			if (Package.Current is not null)
+			{
+				return true;
+			}
+		}
+		catch
+		{
+			// no-op
+		}
+
+		return false;
+	});
+
+	static readonly Lazy<string> fullAppPackageFilePathHolder = new(() =>
+	{
+		return IsPackagedApp
+			? Package.Current.InstalledLocation.Path
+			: AppContext.BaseDirectory;
+	});
+
+	/// <summary>
+	/// Gets if this app is a packaged app.
+	/// </summary>
+	public static bool IsPackagedApp => isPackagedAppHolder.Value;
+
+
+	/// <summary>
+	/// Gets full application path.
+	/// </summary>
+	public static string FullAppPackageFilePath => fullAppPackageFilePathHolder.Value;
+}

src/CommunityToolkit.Maui/Options.shared.cs

@@ -3,6 +3,7 @@
 using CommunityToolkit.Maui.Extensions;
 using CommunityToolkit.Maui.Views;
 #if WINDOWS
+using System.Diagnostics;
 using Microsoft.Maui.LifecycleEvents;
 #endif
 
@@ -86,8 +87,15 @@ public void SetShouldEnableSnackbarOnWindows(bool value)
 
 						else if (Application.Current.Windows.Count is 1)
 						{
-							Microsoft.Windows.AppNotifications.AppNotificationManager.Default.NotificationInvoked += OnSnackbarNotificationInvoked;
-							Microsoft.Windows.AppNotifications.AppNotificationManager.Default.Register();
+							if (AppPackageExtensions.IsPackagedApp)
+							{
+								Microsoft.Windows.AppNotifications.AppNotificationManager.Default.NotificationInvoked += OnSnackbarNotificationInvoked;
+								Microsoft.Windows.AppNotifications.AppNotificationManager.Default.Register();
+							}
+							else
+							{
+								Trace.WriteLine($"{nameof(Alerts.Snackbar)} is not supported on unpackaged Windows apps. {nameof(Alerts.Snackbar)} requires the app to be packaged (MSIX). See https://learn.microsoft.com/dotnet/communitytoolkit/maui/alerts/snackbar for more information.");
+							}
 						}
 					})
 					.OnClosed((_, _) =>
@@ -96,7 +104,7 @@ public void SetShouldEnableSnackbarOnWindows(bool value)
 						{
 							throw new InvalidOperationException($"{nameof(Application)}.{nameof(Application.Current)} cannot be null when Windows are closed");
 						}
-						else if (Application.Current.Windows.Count is 0)
+						else if (Application.Current.Windows.Count is 0 && AppPackageExtensions.IsPackagedApp)
 						{
 							Microsoft.Windows.AppNotifications.AppNotificationManager.Default.NotificationInvoked -= OnSnackbarNotificationInvoked;
 							Microsoft.Windows.AppNotifications.AppNotificationManager.Default.Unregister();
@@ -134,4 +142,4 @@ public void SetPopupOptionsDefaults(DefaultPopupOptionsSettings globalPopupOptio
 	{
 		DefaultPopupOptionsSettings = globalPopupOptionsSettings;
 	}
-}
+}