How to send JSON data from ASP.NET webform vs2010 to web API

[HttpPost]
        public HttpResponseMessage InsertPatDet([FromBody]List<Patient> pt)
        {}

<pre>//Create a request using a URL that can receive a post.         

            string url = "https://url";
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);

            request.Method = "POST";
            // Create POST data and convert it to a byte array.
            string postData = GetJSonData();// "{\"name\":\"Here is the json text 
            byte[] byteArray = Encoding.UTF8.GetBytes(postData);

            // Set the ContentType property of the WebRequest.
            request.ContentType = "application/x-www-form-urlencoded";
            //request.ContentType = "application/json; charset=utf-8 ";
            request.Accept = "application/json";
            // Set the ContentLength property of the WebRequest.
            request.ContentLength = byteArray.Length;
            // Get the request stream.
            Stream dataStream = request.GetRequestStream();
            // Write the data to the request stream.

            //List<byte> ListByte = new List<Byte>(byteArray);

            dataStream.Write(byteArray, 0, byteArray.Length);

            // Close the Stream object.
            dataStream.Close();
            // Get the response.
            WebResponse response = request.GetResponse();
            // Display the status.
            Response.Write(((HttpWebResponse)response).StatusDescription);
            // Get the stream containing content returned by the server.
            dataStream = response.GetResponseStream();
            // Open the stream using a StreamReader for easy access.
            StreamReader reader = new StreamReader(dataStream);
            // Read the content.
            string responseFromServer = reader.ReadToEnd();
            // Display the content.
            Response.Write(responseFromServer);
            // Clean up the streams.
            reader.Close();
            dataStream.Close();
            response.Close();