Question

I am able to send the first request working fine, however I can’t get my head round why it stalls on getting the Stream os = smsRequest.GetRequestStream() the second time.

I am aware that you can’t write to a Request more than once that is why a new instance is created each time.

    public void SendSMS(Dictionary<double, IList<string>> texts)
    {
        if (CreateWebRequest())
        {
            foreach (double mpn in texts.Keys)
            {
                foreach (string sms in texts[mpn])
                {
                    string formParams = string.Format("sendTo=0{0}&selectText=Please+Select...&textMessage={1}&x=28&y=10", mpn, sms);
                    byte[] encodedParams = Encoding.UTF8.GetBytes(formParams);

                    HttpWebRequest smsRequest = CreateSMSRequest(encodedParams);

                    using (Stream os = smsRequest.GetRequestStream())
                    {
                        os.Write(encodedParams, 0, encodedParams.Length);
                        os.Close();
                    }
                }
            }
        }
    }


    private HttpWebRequest CreateSMSRequest(byte[] encodedParams)
    {
        HttpWebRequest smsRequest = (HttpWebRequest)WebRequest.Create(PostUrl);
        smsRequest.Method = WebRequestMethods.Http.Post;
        smsRequest.ContentType = "application/x-www-form-urlencoded";
        smsRequest.ContentLength = encodedParams.Length;
        smsRequest.AllowAutoRedirect = false;
        smsRequest.Credentials = CredentialCache.DefaultNetworkCredentials;
        smsRequest.Headers.Add(HttpRequestHeader.Cookie, _cookieData);

        return smsRequest;
    }

Answer 1

I think your answer is the same as this one:
HttpWebRequest getRequestStream hangs on multiple runs

After your using statement put:

var response = smsRequest.GetResponse() as HttpWebResponse;