C# Post数据

/// <summary>
        /// http Post请求
        /// </summary>
        /// <param name="parameterData">参数</param>
        /// <param name="serviceUrl">访问地址</param>
        /// <param name="ContentType">默认 application/json , application/x-www-form-urlencoded,multipart/form-data,raw,binary </param>
        /// <param name="Accept">默认application/json</param>
        /// <returns></returns>
        public string Post(string parameterData, string serviceUrl, string ContentType = "application/json", string Accept = "application/json")
        {
            //先根据用户请求的uri构造请求地址
            //string serviceUrl = string.Format("{0}/{1}", this.BaseUri, uri);

            //创建Web访问对象
            HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(serviceUrl);
            //把用户传过来的数据转成“UTF-8”的字节流
            byte[] buf = System.Text.Encoding.GetEncoding("UTF-8").GetBytes(parameterData);

            myRequest.Method = "POST";
            //myRequest.Accept = "application/json";
            //myRequest.ContentType = "application/json";  // //Content-Type: application/x-www-form-urlencoded 
            myRequest.AutomaticDecompression = DecompressionMethods.GZip;
            myRequest.Accept = Accept;
            //myRequest.ContentType = ContentType;
            myRequest.ContentType = "application/json";
            myRequest.Accept = "application/json"; ;
            myRequest.KeepAlive = true;
            myRequest.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)";
            myRequest.ContentLength = buf.Length;
            myRequest.MaximumAutomaticRedirections = 1;
            myRequest.AllowAutoRedirect = true;

            //myRequest.Headers.Add("content-type", "application/json");
            //myRequest.Headers.Add("accept-encoding", "gzip");
            //myRequest.Headers.Add("accept-charset", "utf-8");

            //发送请求
            Stream stream = myRequest.GetRequestStream();
            stream.Write(buf, 0, buf.Length);
            stream.Close();

            //通过Web访问对象获取响应内容
            HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
            //通过响应内容流创建StreamReader对象，因为StreamReader更高级更快
            StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
            //string returnXml = HttpUtility.UrlDecode(reader.ReadToEnd());//如果有编码问题就用这个方法
            string returnData = reader.ReadToEnd();//利用StreamReader就可以从响应内容从头读到尾

            reader.Close();
            myResponse.Close();

            return returnData;
        }