sample_demo/ServiceApp/MainWindow.axaml.cs

using Avalonia.Controls;

namespace ServiceApp
{
    public partial class MainWindow : Window
    {
        private string _secretCode = "0000";
        public MainWindow()
        {
            InitializeComponent();
        }

        private void LoginClientButton_Click(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
        {
            new ServiceWindow().Show();
            this.Close();
        }
        private void LoginAdminButton_Click(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
        {
            if (CodeTextBox.Text == _secretCode) {
                new ServiceAdminWindow().Show();
                this.Close();
            }
        }

    }
}