C# - HTTP request with post

HttpWebRequest httpWReq =
    (HttpWebRequest)WebRequest.Create("http://domain.com/page.aspx");

ASCIIEncoding encoding = new ASCIIEncoding();
string postData = "username=user";
postData += "&password=pass";
byte[] data = encoding.GetBytes(postData);

httpWReq.Method = "POST";
httpWReq.ContentType = "application/x-www-form-urlencoded";
httpWReq.ContentLength = data.Length;

using (Stream stream = httpWReq.GetRequestStream())
{
    stream.Write(data,0,data.Length);
}

HttpWebResponse response = (HttpWebResponse)httpWReq.GetResponse();

string responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();