HttpWebRequest 请求

Encoding encoding = Encoding.Default;

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);

            WebHeaderCollection headers = request.Headers;

            headers.Add("sessionid","wxg1214");

            request.Method = "post";

            request.Accept = "text/html, application/xhtml+xml, */*";

            request.ContentType = "application/x-www-form-urlencoded";

            byte[] buffer = encoding.GetBytes(strPostdata);

            request.ContentLength = buffer.Length;

            request.GetRequestStream().Write(buffer, 0, buffer.Length);

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

            using (StreamReader reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.GetEncoding(strEncoding)))

            {

                return reader.ReadToEnd();

            }