FileInfo aFile = new FileInfo(dt.Rows[0]["fj_guid_name"].ToString());
            Response.Clear();
            Response.ContentType = "application/octet-stream";
            string path2 = Server.MapPath(服务器显示名);
                       Response.AddHeader("Content-Disposition", "attachment;FileName=" + System.IO.Path.GetFileName(原名);            Response.WriteFile(path2);
            Response.End();