Can't get Screens in Design Preview in 11.2.0

[Coloryr]

10:03:18.175 [Error] 28276 <= "Unhandled exception. System.InvalidOperationException: Windowing backend wasn't properly initialized."
10:03:18.177 [Error] 28276 <= "   at Avalonia.Controls.WindowBase.get_Screens()"
10:03:18.177 [Error] 28276 <= "   at ColorMC.Gui.UI.Windows.ABaseWindow.SetWindowState() in E:\code\ColorMC\src\ColorMC.Gui\UI\Windows\ABaseWindow.cs:line 114"
10:03:18.178 [Error] 28276 <= "   at ColorMC.Gui.UI.Windows.AMultiWindow.FindGoodPos() in E:\code\ColorMC\src\ColorMC.Gui\UI\Windows\AMultiWindow.cs:line 140"
10:03:18.178 [Error] 28276 <= "   at ColorMC.Gui.UI.Windows.AMultiWindow.InitMultiWindow(BaseUserControl con) in E:\code\ColorMC\src\ColorMC.Gui\UI\Windows\AMultiWindow.cs:line 62"
10:03:18.178 [Error] 28276 <= "   at ColorMC.Gui.UI.Windows.MultiWindow..ctor(BaseUserControl con) in E:\code\ColorMC\src\ColorMC.Gui\UI\Windows\MultiWindow.axaml.cs:line 22"
10:03:18.179 [Error] 28276 <= "   at ColorMC.Gui.Manager.WindowManager.ShowWindow(BaseUserControl con) in E:\code\ColorMC\src\ColorMC.Gui\Manager\WindowManager.cs:line 212"
10:03:18.179 [Error] 28276 <= "   at ColorMC.Gui.Manager.WindowManager.AWindow(BaseUserControl con, Boolean newwindow) in E:\code\ColorMC\src\ColorMC.Gui\Manager\WindowManager.cs:line 238"
10:03:18.179 [Error] 28276 <= "   at ColorMC.Gui.Manager.WindowManager.ShowMain() in E:\code\ColorMC\src\ColorMC.Gui\Manager\WindowManager.cs:line 366"
10:03:18.179 [Error] 28276 <= "   at ColorMC.Gui.Manager.WindowManager.Init(String path) in E:\code\ColorMC\src\ColorMC.Gui\Manager\WindowManager.cs:line 120"
10:03:18.180 [Error] 28276 <= "   at ColorMC.Gui.App.OnFrameworkInitializationCompleted() in E:\code\ColorMC\src\ColorMC.Gui\App.axaml.cs:line 103"
10:03:18.180 [Error] 28276 <= "   at Avalonia.AppBuilder.SetupUnsafe()"
10:03:18.180 [Error] 28276 <= "   at Avalonia.AppBuilder.Setup()"
10:03:18.182 [Error] 28276 <= "   at Avalonia.AppBuilder.SetupWithoutStarting()"
10:03:18.182 [Error] 28276 <= "   at Avalonia.DesignerSupport.Remote.RemoteDesignerEntryPoint.AppInitializer.ConfigureApp(IAvaloniaRemoteTransportConnection transport, CommandLineArgs args, Object obj)"
10:03:18.182 [Error] 28276 <= "   at Avalonia.DesignerSupport.Remote.RemoteDesignerEntryPoint.Main(String[] cmdline)"
10:03:18.183 [Error] 28276 <= "   at Avalonia.Designer.HostApp.Program.Main(String[] args)"

https://github.com/Coloryr/ColorMC/blob/9c0fe2d4e543e38d7d26c06f57a3f77f194c832c/src/ColorMC.Gui/UI/Windows/ABaseWindow.cs#L114

Originally posted by @Coloryr in #17395

[timunie]

Maybe you try to access it too early? Try Dispatcher.UiThread.Post to wait for window to be loaded.

[timunie]

Wait the previewer doesn't know about screens at all afaik. So if you are seeing it in the designer, this is probably by design.

[thevortexcloud]

As was mentioned in the discussion, it does in fact have an implementation for Screens and it does look like it's wired up properly.

#17395 (reply in thread)

I am however not clear why it's not working as it looks fine to me just from looking at the code. The exception can only happen if for some reason Screens returns null, which it should never do.

The only thing that makes sense is if PlatformImpl is null. When that gets made not null though I am not sure.

[maxkatz6]

I actually tried to reproduce this issue using new AvaloniaRider feature, allowing to debug designer process.

It works fine here:

[maxkatz6]

@Coloryr can you try to isolate the issue? Maybe project configuration overrides backend or breaks something unexpectedly.

[Coloryr]

I know what happend, I opened a new window on OnFrameworkInitializationCompleted, and the new window to get the Screens, like your pic.

I actually tried to reproduce this issue using new AvaloniaRider feature, allowing to debug designer process.

It works fine here:

And the new window will also open in preview.

[Coloryr]

AvaloniaApplication1.zip
@maxkatz6

[Coloryr]

11.1.4 is work well