Avalonia/samples/MobileSandbox/MainWindow.xaml.cs

using System;
using Avalonia.Controls;
using Avalonia.Markup.Xaml;

namespace MobileSandbox
{
    public class MainWindow : Window
    {
        public MainWindow()
        {
            this.InitializeComponent();
            //this.ClosingBehavior = WindowClosingBehavior.OwnerWindowOnly;

            //Renderer.DrawFps = true;
            //Renderer.DrawDirtyRects = Renderer.DrawFps = true;
        }

        private void InitializeComponent()
        {
            AvaloniaXamlLoader.Load(this);
        }

        protected override void OnClosing(WindowClosingEventArgs e)
        {
            base.OnClosing(e);

            e.Cancel = true;
            this.Hide();
        }

        protected override void OnClosed(EventArgs e)
        {
            base.OnClosed(e);
        }
    }
}