//流方式下载         protected void ButtonButtonDownload_Click(object sender, EventArgs e)         {            //string fileName = "mychart.png";//客户端保存的文件名             //string filePath = Server.MapPath("/Report/mychart.png");//路径             ////以字符流的形式下载文件             //FileStream fs = new FileStream(filePath, FileMode.Open);            //byte[] bytes = new byte[(int)fs.Length];            //fs.Read(bytes, 0, bytes.Length);            //fs.Close();            //Response.ContentType = "application/octet-stream";            ////通知浏览器下载文件而不是打开             //Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));            //Response.BinaryWrite(bytes);            //Response.Flush();            //Response.End();             string path = Server.MapPath("/Report/mychart.png");//路径             if (File.Exists(path))            {                FileInfo DownloadFile = new FileInfo(path);                Response.Clear();                Response.ClearHeaders();                Response.Buffer = false;                Response.ContentType = "application/octet-stream";                Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(DownloadFile.FullName, System.Text.Encoding.UTF8));                Response.AppendHeader("Content-Length", DownloadFile.Length.ToString());                Response.WriteFile(DownloadFile.FullName);                Response.Flush();                Response.End();            }            //Response.ContentType = "application/octet-stream";            //Response.AddHeader("Content-Disposition", "attachment;filename=mychart.png");            //string filename = Server.MapPath("/Report/mychart.png");            ////指定编码 防止中文文件名乱码             //Response.HeaderEncoding = System.Text.Encoding.GetEncoding("gb2312");            //Response.TransmitFile(filename);         }