httpwebrequest in c#

string url="http://www.contoso.com/default.html";
       string requestData = "";
       string RequestMethod = "POST";
       protected void Page_Load(object sender, EventArgs e)
       {
           try
           {
               /* Create a request using a URL that can receive a post*/
               HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
               /*set header*/
               request.Method = RequestMethod;
               //request.UserAgent="Mozilla/5.0";
               //request.Accept="";
               //request.Connection="";
               //request.ContentLength=requestData.Length;
               //request.ContentType="application/x-www-form-urlencoded";
               //request.Date="";
               //request.Expect="";
               //request.Host="";
               //request.Referer="";
               //request.TransferEncoding="";
               //request.Proxy=null;
               //request.Timeout="";
               //request.Credentials = CredentialCache.DefaultCredentials;
               //*********************
               Byte[] postDataByte = Encoding.ASCII.GetBytes(requestData);
               /* Get the request stream.*/
               Stream requestStream = request.GetRequestStream();
               /*Write the data to the request stream*/
               requestStream.Write(postDataByte, 0, postDataByte.Length);
               /*Close the Stream object*/
               requestStream.Close();
               /*To send the request to the server, call GetResponse*/
               HttpWebResponse response = (HttpWebResponse)request.GetResponse();
               /*Get Some Respone info*/
               Response.Write(((HttpWebResponse)response).StatusDescription);
               Response.Write(((HttpWebResponse)response).Headers);
               /*Get the stream containing content returned by the server*/
               Stream 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();
           }
           catch (Exception)
           {
               Response.Write("An error occured");
           }
       }

Byte[] postDataByte = Encoding.ASCII.GetBytes(requestData);
                /* Get the request stream.*/
                Stream requestStream = request.GetRequestStream();
                /*Write the data to the request stream*/
                requestStream.Write(postDataByte, 0, postDataByte.Length);
                /*Close the Stream object*/
                requestStream.Close();