maui: add shell net8.0 target to support adding package to non-shared project solution structures

Author: jasells

src/LibVLCSharp.MAUI/AppHostBuilderExtensions.cs

@@ -15,7 +15,15 @@ public static MauiAppBuilder UseLibVLCSharp(this MauiAppBuilder builder)
             // Register LibVLCSharp handlers
             builder.ConfigureMauiHandlers(handlers =>
             {
+#if ANDROID || IOS || WINDOWS
                 handlers.AddHandler(typeof(VideoView), typeof(VideoViewHandler));
+#else
+            //.net8 core has no impl, but we need to define it so that the package can be added to a .Net8 x-plat project
+            // for linking purposes.  At runtime, the correct platform-specific lib will be loaded, as any Maui-app solution will 
+            // also contain a platform-specific project targeting one of the supported targets (Android, iOS, WinUI),
+            // or will be a shared-project.
+            throw new NotImplementedException($"This exception means the current target plaftorm: {DeviceInfo.Current.Platform} is not supported or correctly initialized. VLC needs platform-specific libs loaded.");
+#endif
             });
 
             // Configure custom fonts

src/LibVLCSharp.MAUI/Handlers/VideoViewHandler.cs

@@ -5,6 +5,8 @@
 using VideoViewImpl = LibVLCSharp.Platforms.iOS.VideoView;
 #elif WINUI
 using VideoViewImpl = LibVLCSharp.Platforms.Windows.VideoView;
+#else //.Net 8 (core/x-plat)
+using VideoViewImpl = LibVLCSharp.Shared.IVideoView;
 #endif 
 
 namespace LibVLCSharp.MAUI
@@ -25,8 +27,14 @@ protected override VideoViewImpl CreatePlatformView()
         {
 #if ANDROID
             return new VideoViewImpl(Context);
-#else
+#elif IOS || WINUI
             return new VideoViewImpl();
+#else
+            //.net8 core has no impl, but we need to define it so that the package can be added to a .Net8 x-plat project
+            // for linking purposes.  At runtime, the correct platform-specific lib will be loaded, as any Maui-app solution will 
+            // also contain a platform-specific project targeting one of the supported targets (Android, iOS, WinUI),
+            // or will be a shared-project.
+            throw new NotImplementedException($"This exception means the current target plaftorm: {DeviceInfo.Current.Platform} is not supported or correctly initialized. VLC needs platform-specific libs loaded.");
 #endif
         }
     }

src/LibVLCSharp.MAUI/LibVLCSharp.MAUI.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>net8.0-android;net8.0-ios</TargetFrameworks>
+    <TargetFrameworks>net8.0;net8.0-android;net8.0-ios</TargetFrameworks>
     <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('windows'))">$(TargetFrameworks);net8.0-windows10.0.19041</TargetFrameworks>
     <UseMaui>true</UseMaui>
     <SingleProject>true</SingleProject>