public static string unsubResponse(string UnsubURL){try{// Get the ViewState and EventValidation HttpWebRequest request = WebRequest.Create(UnsubURL) as HttpWebRequest;request.Method = "GET";request.KeepAlive = false;// Get the response HttpWebResponse response = request.GetResponse() as HttpWebResponse;Stream responseStream = response.GetResponseStream();StreamReader reader = new StreamReader(responseStream, Encoding.UTF8);string srcString = reader.ReadToEnd();//Get the __VIEWSTATE string viewStateFlag = "id=\"__VIEWSTATE\" value=\"";int i = srcString.IndexOf(viewStateFlag) + viewStateFlag.Length;int j = srcString.IndexOf("\"", i);string viewState = srcString.Substring(i, j - i);// Get the __VIEWSTATEGENERATOR string viewStateGeneratorFlag = "id=\"__VIEWSTATEGENERATOR\" value=\"";i = srcString.IndexOf(viewStateGeneratorFlag) + viewStateGeneratorFlag.Length;j = srcString.IndexOf("\"", i);string viewStateGenerator = srcString.Substring(i, j - i);// Get the __EVENTVALIDATION string EventValidationFlag = "id=\"__EVENTVALIDATION\" value=\"";i = srcString.IndexOf(EventValidationFlag) + EventValidationFlag.Length;j = srcString.IndexOf("\"", i);string eventValidation = srcString.Substring(i, j - i);// Compose the URL viewState = Uri.EscapeDataString(viewState);viewStateGenerator = Uri.EscapeDataString(viewStateGenerator);eventValidation = Uri.EscapeDataString(eventValidation);string unsubButton = Uri.EscapeDataString("Unsubscribe");string formatString = "__VIEWSTATE={0}&__VIEWSTATEGENERATOR={1}&__EVENTVALIDATION={2}&ButtonUnsubscribe={3}"; string postString = string.Format(formatString, viewState, viewStateGenerator, eventValidation, unsubButton);// Change to byte[] byte[] postData = Encoding.ASCII.GetBytes(postString);// Compose the new request request = WebRequest.Create(UnsubURL) as HttpWebRequest;request.Method = "POST";request.KeepAlive = false;request.ContentType = "application/x-www-form-urlencoded";request.ContentLength = postData.Length;Stream outputStream = request.GetRequestStream();outputStream.Write(postData, 0, postData.Length);outputStream.Close();// Get the new response response = request.GetResponse() as HttpWebResponse;responseStream = response.GetResponseStream();reader = new StreamReader(responseStream);srcString = reader.ReadToEnd();return (srcString);}catch (WebException we){Console.WriteLine("Communication error," + we.Message + " please check your connectivity and try again.", "Error");}catch{Console.WriteLine("Unknow error.", "Error");}return (null);}