ขอตัวอย่างการ Send data from C# winform and display the with PHP จากตัวอย่างที่ใช้ เหมือนมันไม่ส่งค่าไปอ่ะครับ ต้องแก้อย่างไร?

using System.IO;
using System.Net;
using System.Web;

            try
            {
                string url = "http://localhost/hospital/get.php";
                string str = "test";
                HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
                req.Method = "POST";
                string Data = "message=" + str;
                byte[] postBytes = Encoding.ASCII.GetBytes(Data);
                req.ContentType = "application/x-www-form-urlencoded";
                req.ContentLength = postBytes.Length;
                Stream requestStream = req.GetRequestStream();
                requestStream.Write(postBytes, 0, postBytes.Length);
                requestStream.Close();

                HttpWebResponse response = (HttpWebResponse)req.GetResponse();
                Stream resStream = response.GetResponseStream();

                var sr = new StreamReader(response.GetResponseStream());
                string responseText = sr.ReadToEnd();


            }
            catch (WebException)
            {

                MessageBox.Show("Please Check Your Internet Connection");
            }

<?php 
    if (isset($_POST['message']))
    {
        $msg = $_POST['message'];
        echo $msg;
    }

?>