[转].net 抓取页面内容查询IP

 　　　　string ip = "202.103.24.68";
            string url = "http://tool.chinaz.com/ip?ip=" + ip;
            byte[] b = new WebClient().DownloadData(url);           
            string str = Encoding.UTF8.GetString(b);
            int star = str.LastIndexOf(ip);
            str = str.Substring(star, 100);