巧妙验证是否ip

CheckIsIp.cs

using System.Net;          
    try
    {
        IPAddress ipTest = IPAddress.Parse(txtBox1.Text);//string转化为ip地址
    }
    catch (Exception)
    {
        toolTip1.Show("ip有误", txtBox1, 2000); //2000是提示显示的时间，单位毫秒
    }

CheckIsIp2.cs

using System.Net;  
            string sqlip = txtBox1.Text.Trim();
            try
            {
                IPAddress ipTest = IPAddress.Parse(sqlip);//如果不能转化为有效ip则抛出异常

                string pattrn = @"((?:(?:25[0-5]|2[0-4]\d|((1\d{2})|([1-9]?\d)))\.){3}(?:25[0-5]|2[0-4]\d|((1\d{2})|([1-9]?\d))))";
                if (!System.Text.RegularExpressions.Regex.IsMatch(sqlip, pattrn)) //正则判断
                {
                    throw new Exception();
                }
                toolTip1.Show("ip正确", txtBox1, 2000); //ip正确
            }
            catch (Exception)
            {
                toolTip1.Show("ip好像有点问题，请检查", txtBox1, 2000);
            }