/// <summary>

        /// Void:设置获取焦点时全选文本

        /// </summary>

        /// <param name="textbox">指定文本框</param>

        public void SetSelectionAllOnGotFocus(TextBox textbox)

        {

MouseButtonEventHandler _OnPreviewMouseDown = (sender, e) =>

            {

                TextBox box = e.Source as TextBox;

                box.Focus();

                e.Handled = true;

            };

            RoutedEventHandler _OnLostFocus = (sender, e) =>

            {

                TextBox box = e.Source as TextBox;

                box.PreviewMouseDown += _OnPreviewMouseDown;

            };

            RoutedEventHandler _OnGotFocus = (sender, e) =>

            {

                TextBox box = e.Source as TextBox;

                box.SelectAll();

                box.PreviewMouseDown -= _OnPreviewMouseDown;

            };

textbox.PreviewMouseDown += _OnPreviewMouseDown;

            textbox.LostFocus += _OnLostFocus;

            textbox.GotFocus += _OnGotFocus;

        }