Hi I Am Not Able To Post Direct Message To Twitter Using Rest Api In C#, Please Help Me Out..

//aouth

            var oauth_token = "XXXX";  //user
            var oauth_token_secret = "XXXX";
            var oauth_consumer_key = "XXXX";  //this is my app
            var oauth_consumer_secret = "XXXX";

            //Request details

            var oauth_version = "1.0";
            var oauth_signature_method = "HMAC-SHA1";
            var oauth_nonce = Convert.ToBase64String(new ASCIIEncoding().GetBytes(DateTime.Now.Ticks.ToString()));
            var timeSpan = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
            var oauth_timestamp = Convert.ToInt64(timeSpan.TotalSeconds).ToString();
           // var resource_url = "https://api.twitter.com/1.1/statuses/update.json";
            var resource_url = "https://api.twitter.com/1.1/direct_messages/new.json";
            var text = "test message";
            var screen_name = "screenname";

            //encrypted oAuth signature

            var baseFormat = "oauth_consumer_key={0}&oauth_nonce={1}&oauth_signature_method={2}" +
                "&oauth_timestamp={3}&oauth_token={4}&oauth_version={5}&screen_name={6}&status={7}";
            //&screen_name={7} &status={6}
            var baseString = string.Format(baseFormat,
                                        oauth_consumer_key,
                                        oauth_nonce,
                                        oauth_signature_method,
                                        oauth_timestamp,
                                        oauth_token,
                                        oauth_version,
                                        Uri.EscapeDataString(screen_name),
                                        Uri.EscapeDataString(text)
                                        );

            baseString = string.Concat("POST&", Uri.EscapeDataString(resource_url),
                         "&", Uri.EscapeDataString(baseString));

            //Encrypt data

            var compositeKey = string.Concat(Uri.EscapeDataString(oauth_consumer_secret),
                        "&", Uri.EscapeDataString(oauth_token_secret));

            string oauth_signature;
            using (HMACSHA1 hasher = new HMACSHA1(ASCIIEncoding.ASCII.GetBytes(compositeKey)))
            {
                oauth_signature = Convert.ToBase64String(
                    hasher.ComputeHash(ASCIIEncoding.ASCII.GetBytes(baseString)));
            }

            //Finish Auth header

            var headerFormat = "OAuth oauth_nonce=\"{0}\", oauth_signature_method=\"{1}\", " +
                   "oauth_timestamp=\"{2}\", oauth_consumer_key=\"{3}\", " +
                   "oauth_token=\"{4}\", oauth_signature=\"{5}\", " +
                   "oauth_version=\"{6}\"";

            var authHeader = string.Format(headerFormat,
                                    Uri.EscapeDataString(oauth_nonce),
                                    Uri.EscapeDataString(oauth_signature_method),
                                    Uri.EscapeDataString(oauth_timestamp),
                                    Uri.EscapeDataString(oauth_consumer_key),
                                    Uri.EscapeDataString(oauth_token),
                                    Uri.EscapeDataString(oauth_signature),
                                    Uri.EscapeDataString(oauth_version)
                            );

            //Disable exprect 100 continue header

            var postBody = "text=" + Uri.EscapeDataString(text);

            ServicePointManager.Expect100Continue = false;

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(resource_url);
            request.Headers.Add("Authorization", authHeader);
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            using (Stream stream = request.GetRequestStream())
            {
                byte[] content = ASCIIEncoding.ASCII.GetBytes(postBody);
                stream.Write(content, 0, content.Length);
            }
            try
            {
                WebResponse response = request.GetResponse();
                ViewBag.Message = response.ToString();
            }
            catch (WebException e)
            {
                ViewBag.Message = e.Status;
            }
            return View();
        }

        public ActionResult About()
        {
            ViewBag.Message = "Your application description page.";

            return View();
        }

        public ActionResult Contact()
        {
            ViewBag.Message = "Your contact page.";
        }