//1測試有效
public static string HttpPost(string sim_uid, string mobile, string msg)
        {

            string _url = string.Format("需要請求的url");
            //json引數
            string jsonParam = Newtonsoft.Json.JsonConvert.SerializeObject(new
            {
                uid = sim_uid,//使用者openid
                mobile = mobile,
                msg 
 
= msg
            });
            var request = (HttpWebRequest)WebRequest.Create(_url);
            request.Method = "POST";
            request.ContentType = "application/json;charset=UTF-8";//ContentType
            byte[] byteData = Encoding.UTF8.GetBytes(jsonParam);
            int length = byteData.Length;
            request.ContentLength 
 
= length;
            Stream writer = request.GetRequestStream();
            writer.Write(byteData, 0, length);
            writer.Close();
            var response = (HttpWebResponse)request.GetResponse();
            var responseString = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding("
 
utf-8")).ReadToEnd();
            return responseString.ToString();
        }

        //2post(未測試)
　　　　　public static string PostReqiest(string url, Dictionary<string, string> dic)
        {
            string result = "";
            ServicePointManager.Expect100Continue = true;
            ServicePointManager.CheckCertificateRevocationList = true;
            ServicePointManager.DefaultConnectionLimit = 100;
            ServicePointManager.SecurityProtocol = (SecurityProtocolType)(0xc0 | 0x300 | 0xc00);
            ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };

            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
            req.ProtocolVersion = HttpVersion.Version10;
            req.KeepAlive = false;
            req.Method = "POST";
            req.ContentType = "application/json";
            #region 新增Post 引數
            StringBuilder builder = new StringBuilder();
            int i = 0;
            foreach (var item in dic)
            {
                if (i > 0)
                    builder.Append("&");
                builder.AppendFormat("{0}={1}", item.Key, item.Value);
                i++;
            }
            byte[] data = Encoding.UTF8.GetBytes(builder.ToString());
            req.ContentLength = data.Length;
            using (Stream reqStream = req.GetRequestStream())
            {
                reqStream.Write(data, 0, data.Length);
                reqStream.Close();
            }
            #endregion
            HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
            Stream stream = resp.GetResponseStream();
            //獲取響應內容
            using (StreamReader reader = new StreamReader(stream, Encoding.UTF8))
            {
                result = reader.ReadToEnd();
            }
            return result;
        }