带进度条的下载

public long DownloadFile( string FileURL, string FileSavePath)
        {
            long Filelength = 0 ;
            long ThisLength = 0 ;
            HttpWebRequest req = HttpWebRequest.Create(FileURL) as HttpWebRequest;
            req.Timeout = 10 * 1000 ;
            req.AllowAutoRedirect = true ;
            label1.Text = " => 正在检测 " + FileSavePath + " ... " ;
            try
            {
                HttpWebResponse res = req.GetResponse() as HttpWebResponse;
                System.IO.Stream stream = res.GetResponseStream();           
                Filelength = res.ContentLength;
                progressBar1.Maximum = ( int )Filelength;
                int allk = ( int )(Filelength / 1024 );
                label1.Text = " => 正在下载 " + FileSavePath + " ... " ;
                byte [] b = new byte [ 1024 ];
                int nReadSize = 0 ;
                nReadSize = stream.Read(b, 0 , 1024 );               

                System.IO.FileStream fs = System.IO.File.Create(FileSavePath);
                try
                {
                   
                    while (nReadSize > 0 )
                    {                                           
                        label1.Refresh();
                        progressBar1.Value += nReadSize;
                        ThisLength += nReadSize;
                        label1.Text = " => 正在下载 " + FileSavePath + " ( " + ( int )(ThisLength / 1024 ) + " K/ " + allk + " K) " ;
                        fs.Write(b, 0 , nReadSize);
                        nReadSize = stream.Read(b, 0 , 1024 );
                    }
                }                   
                finally
                {
                    fs.Close();
                }
                progressBar1.Value = 0 ;
                progressBar1.Maximum = 0 ;
                label1.Text = "" ;
                res.Close();
                stream.Close();
            }
            catch (Exception er)
            {
                throw er;
            }       
            return Filelength;
        }

转载于:https://www.cnblogs.com/guodapeng/archive/2010/01/24/1655386.html