OAuth 2.0 In .NET With Instagram API

I got the answer from the above mentioned SO post about adding POST parameters to an HttpWebRequest. Here are the details of my implementation.

NameValueCollection parameters = new NameValueCollection();parameters.Add("client_id", "3498wjfoi2892jf0j2ij02fjakjf2");parameters.Add("client_secret", "392621gfdlfj2k2hf7g2lfhj2g");parameters.Add("grant_type", "authorization_code");parameters.Add("redirect_uri", "http://localhost:34962/Home/Auth");parameters.Add("code", code);WebClient client = new WebClient();var result = client.UploadValues("https://api.instagram.com/oauth/access_token", parameters);var response = System.Text.Encoding.Default.GetString(result);return View("Index", (object)response);

I spent a lot of time on my task because i didn't see response error.

        try    {        NameValueCollection parameters = new NameValueCollection();        parameters.Add("client_id", "638ed32066b04801bd40aa05c1542915");        parameters.Add("client_secret", "fc67cf3645a648ce82106298010acd65");        parameters.Add("grant_type", "authorization_code");        parameters.Add("redirect_uri", "http://localhost:34962/Test/InstagramCallback");        parameters.Add("code", code);        WebClient client = new WebClient();        var result = client.UploadValues("https://api.instagram.com/oauth/access_token", "POST", parameters);        return Encoding.Default.GetString(result);    }    catch (WebException ex)    {        StreamReader reader = new StreamReader(ex.Response.GetResponseStream());        string line;        StringBuilder result = new StringBuilder();        while ((line = reader.ReadLine()) != null)        {            result.Append(line);        }        return result.ToString();    }