ASP.NET实现文件下载

 string aFile = e.CommandArgument.ToString();
                string aFirstName = aFile.Substring(aFile.LastIndexOf("\") + 1, (aFile.LastIndexOf(".") - aFile.LastIndexOf("\") - 1));  //文件名
                string aLastName = aFile.Substring(aFile.LastIndexOf(".") + 1, (aFile.Length - aFile.LastIndexOf(".") - 1));   //扩展名
               
                string fileName = aFirstName+"."+aLastName;//客户端保存的文件名
                string filePath = Server.MapPath(e.CommandArgument.ToString());//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();