StorageProvider.OpenFolderPickerAsync() not work

[perfect100]

Hi there,
I'm trying to open a folder picker in avalonia , but the behavior is tricky :

Most Pcs work good, but only one Pc can not open the folder, and the UI blocks, OpenFolderPickerAsync() never return.

public async Task<string?> ShowFolderDialogAsync(string title)
{
    var storageFiles = await StorageProvider.OpenFolderPickerAsync(
        new FolderPickerOpenOptions
        {
            Title = title,
        });

    return storageFiles.Count == 0 ? null : storageFiles[0].Path.LocalPath;
}

This method is called in UI thread.

However, after I tried ugly codes, it looks like that the folder is related to the breakpoint when debugging(maybe not).

For context, if I put a breakpoint in L15, the folder picker displays, otherwise, UI blocks even I use await Task.Delay(2000).
So, what happed here? Is the StorageProvider waitting for some condition to meet?

Avalonia : 11.1.0-beta1
OS : Windows 10

[thevortexcloud]

This code in the picture looks odd to me.

• Why are you running a background task for something that is already async?
• Why are you double awaiting?
• What is App.GetCurrentActiveWindow doing?

Also:

• How are you getting the result of ShowFolderDialogAsync? You may have a deadlock somewhere.
• Where are you running this code? You should not be trying to access any view related functionality in your view models, that breaks MVVM and has been known to cause weird issues.
• Tasks are not guaranteed to return on the same thread that started them, do you have any synchronisation stuff (EG mutexes)?

[thevortexcloud]

Does opening a dialogue from within a dialogue work? I have never thought to actually try that since it seems weird to me. Are you sure the window is not actually opening and has not just gone behind another dialogue?

[perfect100]

Does opening a dialogue from within a dialogue work?

Yes, I create a new project. Open a new dialogue from main window, and then open the folder picker from the dialogue, it works.

Are you sure the window is not actually opening and has not just gone behind another dialogue?

The folder picker never shows up actually. I can not find any dialogue behind.
Anyway, maybe some logic issue in my code, I'm refactoring currently.
Many thanks.

[perfect100]

After my investigation, I find that there're some weird issue when calling FolderPicker.

Avalonia/src/Windows/Avalonia.Win32/Win32StorageProvider.cs

Line 155 in b30894c

var showResult = frm.Show(_windowImpl.Handle.Handle);

If I debug the code (it means how to set the property of the frm), then the folder will show;
But, I just run the code without debug, then the var showResult = frm.Show(_windowImpl.Handle.Handle); will never return.

So how I can diagnose the issue?

Avalonia Version : 11.1.0-beta1

[jp2masa]

Did you try adding the STAThread attribute to Main? I don't know much about COM, but I think it's worth a try.

[perfect100]

It already has the STAThread attribute there...

[perfect100]

The root cause is that the Main entrance function is async, which broken the [STA]...

I have created a issue here : #15806

Thanks all @thevortexcloud @jp2masa