public static string VoteOnce(string url, string PostStr)
        {
            //创建HttpWebRequest发送请求用
            HttpWebRequest hwrq = (HttpWebRequest)WebRequest.Create(url);
            //下面是相关数据头和数据发送方法
            hwrq.Accept = "application/x-shockwave-flash, image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*";
            hwrq.Referer = url;
            hwrq.ContentType = "application/x-www-form-urlencoded";
            hwrq.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727; MAXTHON 2.0)";
            hwrq.KeepAlive = true;
            hwrq.Method = "POST";
   

            UTF8Encoding utf8 = new UTF8Encoding();
            byte[] bytePost = utf8.GetBytes(PostStr);
            hwrq.ContentLength = bytePost.Length;

            //下面是发送数据的字节流
            Stream MyStream = hwrq.GetRequestStream();
            MyStream.Write(bytePost, 0, bytePost.Length);
            MyStream.Close();//记得要结束字节流啊

            HttpWebResponse hwrp = (HttpWebResponse)hwrq.GetResponse();
            StreamReader MyStreamR = new StreamReader(hwrp.GetResponseStream(), Encoding.Default);
            string result = MyStreamR.ReadToEnd();
            MyStreamR.Close();

            return result;
        }