C# ตรวจสอบ URL ว่าสามารถอ่านค่าได้หรือไม่ครับ C# Check URL

        private bool CheckURL(string url)
        {
            //Update UI
            lStatus.Text = "Checking URL...";
            lStatus.ForeColor = Color.Black;
            this.Cursor = Cursors.WaitCursor;
            Application.DoEvents();

            Uri urlCheck = new Uri(url);

            WebRequest request = WebRequest.Create(urlCheck);
            request.Timeout = 15000;

            WebResponse response;
            try
            {
                //get URL web response
                response = request.GetResponse();
            }
            catch (Exception)
            {
                this.Cursor = Cursors.Default;
                return false; //url does not exist
            }            

            string responseURL = response.ResponseUri.ToString();

            //Update UI
            this.Cursor = Cursors.Default;
            Application.DoEvents();
            if (string.Compare(responseURL, urlCheck.ToString(), true) != 0) //it was redirected, check to see if redirected to error page
                   return !(responseURL.IndexOf("404.php") > -1 ||
                          responseURL.IndexOf("500.php") > -1 ||
                          responseURL.IndexOf("404.htm") > -1 ||
                          responseURL.IndexOf("500.htm") > -1);
            else
                return true; //everything okay
        }