Uri myUri =new Uri(@sURL);
WebRequest wrq = WebRequest.Create(myUri);
WebResponse wrs = wrq.GetResponse(); //引发WebException
Stream strm = wrs.GetResponseStream();
StreamReader sr = new StreamReader(strm, System.Text.Encoding.GetEncoding( "gb2312" ));
//读取网页
sHTML = sr.ReadToEnd();