textbox框的输入限制

 为了使textbox框能够限制输入的字符，可以这样：

        private void txtPostalCode_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (Char.IsDigit(e.KeyChar))
            {
                e.Handled = false;
            }
            else if (e.KeyChar.Equals('-'))
            {
                e.Handled = false;
            }
            else if (e.KeyChar.Equals('/b'))
            {
                e.Handled = false;
            }
            else
            {
                e.Handled = true;
            }
        }