void OnPreviewKeyDown(object sender, System.Windows.Input.KeyEventArgs e) { if (e.Key == Key.Back) { AssociatedObject.EditValue = null; } else if (e.Key >= Key.A && e.Key < Key.Z) { AssociatedObject.EditValue = HotKeyHelper.GetString(e.Key, e.KeyboardDevice.Modifiers); } e.Handled = true; }