c#中解决只能让用户输入数字的方法

  private void txtNewPort_KeyPress(object sender, KeyPressEventArgs e)
        {
            e.Handled = e.KeyChar < '0' || e.KeyChar > '9';
            if (e.KeyChar == (char)8)//8指的是back键
            {
                e.Handled = false;//false表示可以操作
            }
            if (e.Handled)
            {
                MessageBox.Show("请输入数字");
            }
        }