WinUI: Changed the way to detect a WinUI application

[optsing]

Description of Change

Prior to this change, LibVLCSharp detected WinUI usage by TargetFramework.StartsWith('net6.0-windows10'), which was not always correct.
Microsoft recommends specifying <UseWinUI>true</UseWinUI> for WinUI applications, which seems to be a more correct way to detect a WinUI application.

Issues Resolved

None

API Changes

None

Platforms Affected

• Windows
• WinUI

Behavioral/Visual Changes

None

Before/After Screenshots

Not applicable

Testing Procedure

PR Checklist

• Rebased on top of the target branch at time of PR
• Changes adhere to coding standard

[mfkl]

CI complains

2024-07-04T17:27:45.9959683Z   D:\a\1\s\samples\LibVLCSharp.WinUI.Sample\MainWindow.xaml.cs(1,19): error CS0234: The type or namespace name 'Platforms' does not exist in the namespace 'LibVLCSharp' (are you missing an assembly reference?) [D:\a\1\s\samples\LibVLCSharp.WinUI.Sample\LibVLCSharp.WinUI.Sample.csproj]
2024-07-04T17:27:45.9960821Z   D:\a\1\s\samples\LibVLCSharp.WinUI.Sample\MainWindow.xaml.cs(36,59): error CS0246: The type or namespace name 'InitializedEventArgs' could not be found (are you missing a using directive or an assembly reference?) [D:\a\1\s\samples\LibVLCSharp.WinUI.Sample\LibVLCSharp.WinUI.Sample.csproj]
2024-07-04T17:27:45.9962065Z   D:\a\1\s\samples\LibVLCSharp.WinUI.Sample\obj\x64\Release\net6.0-windows10.0.19041.0\MainWindow.g.i.cs(22,37): error CS0234: The type or namespace name 'Platforms' does not exist in the namespace 'LibVLCSharp' (are you missing an assembly reference?) [D:\a\1\s\samples\LibVLCSharp.WinUI.Sample\LibVLCSharp.WinUI.Sample.csproj]

[mfkl]

I could be wrong, but I think you're confusing the csproj setup between an app and a library.

UseWinUI is currently set in the app sample, not the library project. So when LibVLCSharp is built, UseWinUI will always be false.

Additionally, I believe that targeting net6.0-win10 does not necessarily mean you are building a WinUI-based app. You might be building a CLI app that does not depend on WinUI but needs to access Win10 APIs.

[mfkl]

Could you please share a minimal sample (ideally a sample from your fork from this repo) that reproduces your issue?

[mfkl]

Closing for inactivity. Feel free to re-open with updates.