HTTP请求

/// <summary>
        /// 提交数据请求
        /// </summary>
        /// <param name="POSTURL">请求提交的地址 如：https://car.etaiping.com:6004/ecms2/portal/商户号/请求类型（接口名称）
        /// <param name="PostData">提交的数据(字符串)</param>
        /// <returns></returns>
        public string RequestData(string PostData)
        {
            string POSTURL = string.Format("https://www.sina.com.cn");

            Encoding myEncoding = Encoding.GetEncoding("UTF-8");
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;
            //将提交的字符串数据转换成字节数组
            //注意提交的编码,这里默认的是Default：系统当前编码
            byte[] postData = myEncoding.GetBytes(PostData);
            //设置提交的相关参数 
            HttpWebRequest request = WebRequest.Create(POSTURL) as HttpWebRequest;

            //实例化一个证书
            //X509Certificate2 cerCaiShang = GetCertificate();
            ServicePointManager.ServerCertificateValidationCallback = (sender, certificate, chain, sslPolicyErrors) => true;
            //request.ClientCertificates.Add(cerCaiShang);
            request.Method = "POST";
            request.KeepAlive = true;
            //request.AllowAutoRedirect = true;
            request.ProtocolVersion = HttpVersion.Version10;
            request.ContentType = "text/xml;charset=utf-8";
            //request.ContentType = "application/x-www-form-urlencoded";
            request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727; .NET CLR  3.0.04506.648; .NET CLR 3.5.21022; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)";
            CookieContainer cookieContainer = new CookieContainer();
            request.CookieContainer = cookieContainer;
            request.ContentLength = postData.Length;
            //request.ClientCertificates.Add(new X509Certificate("C:\CerPath\_Cer.cer"));//证书路径
            

            #region 传输数据
            try
            {
                using (Stream writer = request.GetRequestStream())
                {
                    writer.Write(postData, 0, postData.Length);
                }
            }
            catch (Exception ex)
            {
                return ex.Message;
            }

            #endregion

            #region 接收返回的数据
            string srcString = string.Empty;
            try
            {
                HttpWebResponse response = request.GetResponse() as HttpWebResponse;
                using (Stream sr = response.GetResponseStream())
                {
                    using (StreamReader reader = new StreamReader(sr, myEncoding))
                    {
                        srcString = reader.ReadToEnd();
                    }
                }
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
            #endregion
            return srcString;
        }