C# 请求Https

/// <summary>
        /// Get请求
        /// </summary>
        /// <param name="Url"></param>
        /// <param name="postDataStr"></param>
        /// <returns></returns>
        public static string HttpGet(string Url, string postDataStr)
        {
            try
            {
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);

                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url + (postDataStr == "" ? "" : "?") + postDataStr);
                request.Proxy = null;
                request.KeepAlive = false;
                request.Method = "GET";
                request.ContentType = "application/json; charset=UTF-8";
                request.AutomaticDecompression = DecompressionMethods.GZip;

                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                Stream myResponseStream = response.GetResponseStream();
                StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.UTF8);
                string retString = myStreamReader.ReadToEnd();

                myStreamReader.Close();
                myResponseStream.Close();

                if (response != null)
                {
                    response.Close();
                }
                if (request != null)
                {
                    request.Abort();
                }

                return retString;
            }
            catch (Exception ex)
            {
                return "";
            }

        }

        public static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
        { // Always accept
            Console.WriteLine("accept " + certificate.GetName());
            return true; //总是接受
        }

 /// <summary>
        /// post请求 string ss= HttpPost("http://localhost:41558/api/Demo/PostXXX", "{Code:"test089",Name:"test1"}");
        /// </summary>
        /// <param name="url"></param>
        /// <param name="body"></param>
        /// <returns></returns>
        public static string HttpPost(string url, string body)
        {
            try
            {
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);

                Encoding encoding = Encoding.UTF8;
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                request.Method = "POST";
                request.Accept = "text/html, application/xhtml+xml, */*";
                request.ContentType = "application/json";

                byte[] buffer = encoding.GetBytes(body);
                request.ContentLength = buffer.Length;
                request.GetRequestStream().Write(buffer, 0, buffer.Length);
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
                {
                    return reader.ReadToEnd();
                }
            }
            catch (Exception ex)
            {
                return "";
            }
        }


        /// <summary>
        /// post请求 string ss= HttpPost("http://localhost:41558/api/Demo/PostXXX", "{Code:"test089",Name:"test1"}");
        /// </summary>
        /// <param name="url"></param>
        /// <param name="body"></param>
        /// <returns></returns>
        public static string HttpPut(string url, string body)
        {
            //ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
            Encoding encoding = Encoding.UTF8;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "Put";
            request.Accept = "text/html, application/xhtml+xml, */*";
            request.ContentType = "application/json";

            byte[] buffer = encoding.GetBytes(body);
            request.ContentLength = buffer.Length;
            request.GetRequestStream().Write(buffer, 0, buffer.Length);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
            {
                return reader.ReadToEnd();
            }
        }

        /// <summary>
        /// post请求 string ss= HttpPost("http://localhost:41558/api/Demo/PostXXX", "{Code:"test089",Name:"test1"}");
        /// </summary>
        /// <param name="url"></param>
        /// <param name="body"></param>
        /// <returns></returns>
        public static string HttpDelete(string url, string body)
        {
            //ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
            Encoding encoding = Encoding.UTF8;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "Delete";
            request.Accept = "text/html, application/xhtml+xml, */*";
            request.ContentType = "application/json";

            byte[] buffer = encoding.GetBytes(body);
            request.ContentLength = buffer.Length;
            request.GetRequestStream().Write(buffer, 0, buffer.Length);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
            {
                return reader.ReadToEnd();
            }
        }