在winfrom中如何限制只能输入数字

//在控件的KeyPress事件中 

 private void txtPhoneNo_KeyPress(object sender, KeyPressEventArgs e)
        {
            char result=e.KeyChar;
         
            if (char.IsDigit(result)||result==8)
            {
                e.Handled = false;
            }
            else
            {
                e.Handled = true;
            }
        }