【原创】验证代理IP是否有用

        /// <summary>
        /// 验证代理IP是否有用
        /// </summary>
        /// <param name="ip">IP地址</param>
        /// <param name="port">端口号</param>
        /// <returns>可用返回true</returns>
        static bool IsEnabled(string ip, int port)
        {
            try
            {
                HttpWebRequest Req = (HttpWebRequest)WebRequest.Create("http://www.whatismyip.com.tw/");
                WebProxy proxyObject = new WebProxy(ip, port);//IP地址,端口号
                Req.Proxy = proxyObject; //设置代理
                Req.UserAgent = "Mozilla/5.0 (Windows NT 6.1; rv:31.0) Gecko/20100101 Firefox/31.0";
                HttpWebResponse Resp = (HttpWebResponse)Req.GetResponse();
                Encoding code = Encoding.GetEncoding("UTF-8");
                using (StreamReader sr = new StreamReader(Resp.GetResponseStream(), code))
                {
                    if (sr != null)
                    {

                        string strHtml = sr.ReadToEnd();

                        MatchCollection mc = Regex.Matches(strHtml, "<h2>(?<text>.*?)</h2>", RegexOptions.IgnoreCase);
                        if (mc.Count > 0)
                        {
                            GroupCollection gc = mc[0].Groups;
                            if (ip == gc["text"].Value)
                            {
                                return true;
                            }
                        }
                    }
                }
            }
            catch
            {
                return false;
            }
            return false;
        }