X11: System.Exception: Unable to initialize GTK on separate thread

Describe the bug The exception in the title is thrown when opening a file dialog.

To Reproduce Create a new project using the Avalonia .NET Core App template. (NOT THE MVVM ONE). Here’s the relevant code that triggers the exception:

<!-- MainWindow.axaml -->
<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="JGCodes.AvaloniaTest.MainWindow"
        Title="Avalonia Test">
    <Button Name="SpecialButton" Click="OnButtonClick">Open, sesame!</Button>
</Window>

// MainWindow.axaml.cs
using Avalonia.Controls;
using Avalonia.Interactivity;

namespace JGCodes.AvaloniaTest
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        public async void OnButtonClick(object sender, RoutedEventArgs e)
        {
            OpenFileDialog ofd = new();
            await ofd.ShowAsync(this);
        }
    }
}

Run the project, click the button, and receive the above exception.

Expected behavior A file dialog should appear.

Desktop (please complete the following information):

• OS: Linux (ArcoLinux, KDE, XWayland)
• Version 0.10.17

Additional context N/A

[maxkatz6]

Should be fixed with 11.0 previews, as we use FreeDesktop dialogs instead, when available. Also, GTK initialization was changed, which might also solve old issue, if FreeDesktop is not available.

Please let us know if it’s still a problem in 11.0 previews.

[brunzefb]

FWIW, my workaround. below the ViewModel code, use binding to the view model. You do need kdialog installed on KDE systems for this to work.

     <Button 
                Command="{Binding OpenFileCommand}"
                Margin="0,0,10,0"
                VerticalAlignment="Center" 
                HorizontalAlignment="Right"
                Height="26"
                FontSize="11"
                Content="_Open..." />

Here the ViewModel code

    public void OpenFileCommand()
    {
        var helper = new OpenDlgHelper();
        var result = helper.GetFileName();
        HexFile = string.IsNullOrEmpty(result) ? _prompt : result;
    }

And here the helper class

using System.Diagnostics;
using System.IO;
using System.Text;
using System.Threading.Tasks;

namespace QMK_Toolbox;

public class OpenDlgHelper
{
    public StringBuilder sb { get; set; }
    
    public string GetFileName()
    {
        RunProcessAsync("/usr/bin/kdialog", "--getopenfilename /home/").Wait();
        return sb.ToString();
    }

    private async Task<int> RunProcessAsync(string command, string args)
    {
        sb = new StringBuilder();
        using (var process = new Process
               {
                   StartInfo =
                   {
                       FileName = command,
                       Arguments = args,
                       WorkingDirectory = Path.GetDirectoryName(command),
                       UseShellExecute = false,
                       CreateNoWindow = true,
                       RedirectStandardOutput = true,
                       RedirectStandardError = true
                   },
                   EnableRaisingEvents = true
               })
        {
            return await RunProcessAsync(process).ConfigureAwait(false);
        }
    }

    private Task<int> RunProcessAsync(Process process)
    {
        var tcs = new TaskCompletionSource<int>();

        process.Exited += (sender, e) =>
        {
            process.WaitForExit();
            tcs.SetResult(process.ExitCode);
        };

        process.OutputDataReceived += ProcessOutput;
        process.ErrorDataReceived += ProcessErrorOutput;

        bool started = process.Start();
        if (!started)
        {
            Debug.WriteLine($"Could not start process: {process}");
        }

        process.BeginOutputReadLine();
        process.BeginErrorReadLine();

        return tcs.Task;
    }

    private void ProcessOutput(object sender, DataReceivedEventArgs e)
    {
        if (e.Data != null)
        {
            sb.Append(e.Data);
        }
    }

    private void ProcessErrorOutput(object sender, DataReceivedEventArgs e)
    {
        if (e.Data != null)
        {
            Debug.WriteLine(e.Data);
        }
    }
}