c#按键Up和Down对Textbox的内容加1减1

        private void textBox_proc1value_KeyDown(object sender, KeyEventArgs e)

        {

            Keys key = e.KeyCode;

            if (e.Control!=true)//如果没按Ctrl键

            return;

           TextBox textBox = sender as TextBox;

           switch (key)

           {

               case Keys.Up:

                   textBox.Text = (int.Parse(textBox.Text.Trim()) + 1).ToString();

                   break;

               case Keys.Down:

                   textBox.Text = (int.Parse(textBox.Text.Trim()) - 1).ToString();

                   break;

           }

        }