c# 擷取頁面源碼

/// <summary>        /// 擷取原始碼        /// </summary>        /// <param name="url"></param>        /// <param name="encoding"></param>        /// <returns></returns>        public string GetPage(string url, string PointStr,Encoding Ec        {            HttpWebRequest request = null;            HttpWebResponse webResponse = null;            try            {                request = (HttpWebRequest)WebRequest.Create(url);                request.AllowAutoRedirect = true;                request.Timeout = 5000;                request.ReadWriteTimeout = 5000;                //request.KeepAlive = true;                request.Method = "GET";                //request.ImpersonationLevel = System.Security.Principal.TokenImpersonationLevel.Anonymous;                request.UserAgent = "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)";                webResponse = (HttpWebResponse)request.GetResponse();                using (System.IO.Stream stream = webResponse.GetResponseStream())                {                    using (System.IO.StreamReader reader2 = new StreamReader(stream, Ec))                    {                        return reader2.ReadToEnd();                    }                }            }            catch            {                //Main.St.Add(url+"----"+ex.ToString());                return "";            }            finally            {                if (request != null)                {                    request = null;                }                if (webResponse != null)                {                    webResponse.Close();                    webResponse = null;                }            }        }