wabbajack/Wabbajack.Launcher/App.axaml.cs

using Avalonia;
using Avalonia.Controls.ApplicationLifetimes;
using Avalonia.Markup.Xaml;
using Microsoft.Extensions.DependencyInjection;
using Wabbajack.Launcher.ViewModels;
using Wabbajack.Launcher.Views;

namespace Wabbajack.Launcher;

public class App : Application
{
    public override void Initialize()
    {
        AvaloniaXamlLoader.Load(this);
    }

    public override void OnFrameworkInitializationCompleted()
    {
        
        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
            desktop.MainWindow = new MainWindow
            {
                DataContext = Program.Services.GetRequiredService<MainWindowViewModel>()
            };

        base.OnFrameworkInitializationCompleted();
    }
}