XThread02

using System.Windows;

namespace WpfCrossThread {

    public partial class MainWindow : Window {
        private delegate void EnterTextDelegate();
        public MainWindow() {
            InitializeComponent();
        }

        private void button_Click(object sender, RoutedEventArgs e) {
            var del = new EnterTextDelegate(EnterText);
            del.BeginInvoke(null, null);
        }
        private void EnterText() {
           MyTextBox.Text = "this may make it fail";
        }
    }
}