用C# HttpWebRequest与RestSharp.dll请求代码

        public static string PostRequest(string Url, string Param)
        {
            HttpWebRequest request;
            HttpWebResponse response;            string strURL = Url;            string StrDate = "";
            string strValue = "";
            try
            {
                request = (HttpWebRequest)WebRequest.Create(strURL);
                request.Method = "POST";
                request.ContentType = "application/json;";
                request.Timeout = 20000;
                byte[] Data = Encoding.UTF8.GetBytes(Param);
                request.GetRequestStream().Write(Data, 0, Data.Length);
                response = (HttpWebResponse)request.GetResponse();
                request.GetRequestStream().Close();
            }
            catch (WebException ex)
            {
                strValue = ex.Message;
                response = (HttpWebResponse)ex.Response;

            }
            try
            {
                Stream Data_S = response.GetResponseStream();
                StreamReader Reader = new StreamReader(Data_S, Encoding.UTF8);
                while ((StrDate = Reader.ReadLine()) != null)
                {
                    strValue += StrDate + "\r\n";
                }
                Data_S.Close();
            }
            catch (Exception ex)
            {
                strValue = ex.Message;
            }
            return strValue;        }

        public static string PostRequest(string Url)
        {
            HttpWebRequest request;
            HttpWebResponse response;            string strURL = Url;
            string StrDate = "";
            string strValue = "";
            try
            {
                request = (HttpWebRequest)WebRequest.Create(strURL);
                request.Method = "POST";
                request.ContentType = "application/json;charset=UTF-8";
                response = (HttpWebResponse)request.GetResponse();
            }
            catch (WebException ex)
            {
                strValue = ex.Message;
                response = (HttpWebResponse)ex.Response;
            }
            try
            {
               Stream Data_S = response.GetResponseStream();                StreamReader Reader = new StreamReader(Data_S, Encoding.UTF8);
                while ((StrDate = Reader.ReadLine()) != null)
                {
                    strValue += StrDate + "\r\n";
                }
                Data_S.Close();            }
            catch (Exception ex)
            {
                strValue = ex.Message;
            }
            return strValue;
        }

        public static string PostRequest(string Url, string Param)
        {
            string strValue = string.Empty;
            try
            {
                var client = new RestClient(Url);
                var request = new RestRequest(Method.POST);
                request.RequestFormat = DataFormat.Json;
                var body = Param;
                request.AddParameter("application/json; charset=utf-8", JsonConvert.SerializeObject(body), ParameterType.RequestBody);
                IRestResponse response = client.Execute(request);
                var responseContent = response.Content;
                strValue = responseContent;
            }
            catch (Exception ex)
            {
                strValue = ex.Message;
            }
            return strValue;
        }