Add support for NativeControlHost inside a UserControl

Is your feature request related to a problem? Please describe.

https://stackoverflow.com/questions/68292849/avaloniaui-cannot-embed-videoview-control-libvlcsharp-in-a-usercontrol

It seems the native window handle is not surfaced when the NativeControlHost is positioned inside a UserControl.

Describe the solution you’d like

Essentially a more advanced version of https://github.com/AvaloniaUI/Avalonia/blob/master/samples/interop/NativeEmbedSample/EmbedSample.cs

Being able to do so would improve the NativeControlHost support and help building native-based reusable components.

Describe alternatives you’ve considered

Other than that, the view is working fine on its own https://code.videolan.org/videolan/LibVLCSharp/-/blob/3.x/src/LibVLCSharp.Avalonia/VideoView.cs

Additional context

• https://stackoverflow.com/questions/68292849/avaloniaui-cannot-embed-videoview-control-libvlcsharp-in-a-usercontrol
• https://code.videolan.org/videolan/LibVLCSharp/-/blob/3.x/src/LibVLCSharp.Avalonia/VideoView.cs

[radiolondra]

All the links updated (latest libs and samples versions)

Avalonia Unofficial LibVLCSharp Links

VLC video player inside an Avalonia Window/UserControl embedding single static customizable control (e.g.player buttons) LibVLCSharp.Avalonia.Unofficial

VLC video player inside an Avalonia Window/UserControl embedding multiple draggable customizable controls (e.g.player buttons, images,…) LibVLCSharp.Avalonia.Unofficial.UCanvas

LibVLCSharp.Avalonia.Unofficial Samples LibVLCSharp.Avalonia.Unofficial.Samples

LibVLCSharp.Avalonia.Unofficial.UCanvas sample LibVLCSharp.Avalonia.Unofficial.UCanvas.Samples

YAMP 2 - Open source video player sample using LibVLCSharp.Avalonia.Unofficial library Github sources Watch YAMP2 in action

[radiolondra]

New test on Raspberry Pi (DietPi with MATE or Xfce)

It works fine!

Transparency and Opacity are fully honored.

In my opinion, the problem is not Avalonia vs Raspberry, the problem is what is installed or not in Raspberry.

With DietPi OS and MATE (or Xfce) as X, the sample works perfectly. And playback is smooth without jerks, interruptions or whatever.

As root, I installed libx11-dev, libvlc-dev and vlc, copied the published sample (built in Windows 10 with dotnet publish -c release -f net5.0 -r linux-arm), chmod 777 the whole folder content and ran the sample. It has to be ran as root or with sudo.