using System; using System.Windows; using System.Windows.Input; using System.Windows.Media; public class MainClass : Window { [STAThread] public static void Main() { Application app = new Application(); app.Run(new MainClass()); } public MainClass() { Content = ""; } protected override void OnTextInput(TextCompositionEventArgs args) { base.OnTextInput(args); string str = Content as string; if (args.Text == "\b") { if (str.Length > 0) str = str.Substring(0, str.Length - 1); } else { str += args.Text; } Content = str; } }