c#获取网页的HTML源码

原文：http://topic.csdn.net/u/20081125/21/b05ebc85-3591-4d65-8602-66af58ef825f.html?seed=812988667 

using System.Net ;

using System.IO ;

/// <summary>
        /// 获取网页的HTML代码
        /// </summary>
        /// <param name="url">Url地址(http://www.baidu.com/)</param>
        /// <param name="Prog">进度条</param>
        /// <returns></returns>
        public static string GetUrlData(string url,ProgressBar Prog)
        {
            HttpWebResponse res = null;
            HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(url);
                res = (HttpWebResponse)req.GetResponse();
            long  totalBytes = res.ContentLength;
            Stream input = null;
            input = res.GetResponseStream();
            int totalDownloadedByte = 0;
            byte[] by = new byte[10245];
            string Content=null; 
            System.Text.Encoding encoder = System.Text.Encoding.GetEncoding("GB2312");
            do
            {
                totalDownloadedByte = input.Read(by, 0, (int)by.Length); 
                Content+=encoder.GetString(by, 0, totalDownloadedByte);
                if (Prog.Value + totalDownloadedByte <= Prog.Maximum)
                {
                    Prog.Value += totalDownloadedByte;
                    Application.DoEvents();
                }
                else
                {
                    Prog.Value = Prog.Maximum;
                }               
                   
            }
            while (totalDownloadedByte != 0);
            
            res.Close();
            Prog.Value =0 ;
            return Content;
        }