根据IP获取省市 .

public class IPAddress
    {
        /// <summary>
        /// 得到真实IP以及所在地详细信息（Porschev）
        /// </summary>
        /// <returns></returns>
        public string GetIpDetails()
        {
            string url = "http://www.ip138.com/ips8.asp";   //设置获取IP地址和国家源码的网址
            string regStr = "(?<=<td\\s*align=\\\"center\\\">)[^<]*?(?=<br/><br/></td>)";
            string ipRegStr = "((2[0-4]\\d|25[0-5]|[01]?\\d\\d?)\\.){3}(2[0-4]\\d|25[0-5]|[01]?\\d\\d?)";    //IP正则
            string ip = string.Empty;   //IP地址
            string country = string.Empty;  //国家
            string adr = string.Empty;   //省市
            string html = GetHtml(url);       //得到网页源码
            Regex reg = new Regex(regStr, RegexOptions.None);
            Match ma = reg.Match(html); html = ma.Value;
            Regex ipReg = new Regex(ipRegStr, RegexOptions.None);
            ma = ipReg.Match(html);
            ip = ma.Value;     //得到IP
            int index = html.LastIndexOf("：") + ;
            country = html.Substring(index);                   //得到国家
            adr = GetAdrByIp(ip);
            return "IP：" + ip + "  国家：" + country + "  省市：" + adr;
        }
        /// <summary>
        /// 通过IP得到IP所在地省市（Porschev）
        /// </summary>
        /// <param name="ip"></param>
        /// <returns></returns>
        public string GetAdrByIp(string ip)
        {
            string url = "http://www.cz88.net/ip/?ip=" + ip;
            string regStr = "(?<=<span\\s*id=\\\"cz_addr\\\">).*?(?=</span>)";
            string html = GetHtml(url);       //得到网页源码
            Regex reg = new Regex(regStr, RegexOptions.None);
            Match ma = reg.Match(html);
            html = ma.Value;
            string[] arr = html.Split(' ');
            return arr[];
        }

        /// <summary>
        /// 获取HTML源码信息(Porschev)
        /// </summary>
        /// <param name="url">获取地址</param>
        /// <returns>HTML源码</returns>
        public string GetHtml(string url)
        {
            string str = "";
            try
            {
                Uri uri = new Uri(url);
                WebRequest wr = WebRequest.Create(uri);
                Stream s = wr.GetResponse().GetResponseStream();
                StreamReader sr = new StreamReader(s, Encoding.Default);
                str = sr.ReadToEnd();
            }
            catch (Exception e)
            {
            }
            return str;
        }
    }