GSS2Rework/GSS2.Test/App.axaml.cs

using Avalonia;
using Avalonia.Controls.ApplicationLifetimes;
using Avalonia.Markup.Xaml;

using GSS2.Test.ViewModels;
using GSS2.Test.Views;

namespace GSS2.Test;

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

    public override void OnFrameworkInitializationCompleted()
    {
        if (ApplicationLifetime is null)
            throw new InvalidOperationException("Application framework initialization cannot be fulfilled, ApplicationLifetime is null");

        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
        {
            Console.WriteLine("Application running in classic style");
            desktop.Startup += (_, _) => Program.ApplicationHost.RunAsync();
            desktop.Exit += (_, _) => Program.ApplicationHost.StopAsync();

            desktop.MainWindow = new MainWindow()
            {
                DataContext = Program.ApplicationHost.Services.GetRequiredService<MainWindowViewModel>()
            };
        }
        else if (ApplicationLifetime is ISingleViewApplicationLifetime singleView)
        {
            Console.WriteLine("Application running in single view style");
            var loggerFactory = Program.ApplicationHost.Services.GetRequiredService<ILoggerFactory>();
            var logger = loggerFactory.CreateLogger<MainView>();
            singleView.MainView = new MainView(logger)
            {
                DataContext = Program.ApplicationHost.Services.GetRequiredService<MainViewModel>()
            };
        }
        else
            throw new InvalidOperationException($"Application framework initialization cannot be fulfilled, ApplicationLifetime has unknown type inherited from: {string.Join(", ", ApplicationLifetime.GetType().GetInterfaces().Select(i => i.FullName))}");
        base.OnFrameworkInitializationCompleted();
    }
}