Byte[] fileBytes = dt.Rows[0][0] as byte[];
                    Response.Buffer = true;
                    Response.ClearContent();
                    Response.ClearHeaders();
                    //指定http名称和值 
                    Response.AddHeader("content-disposition", "attachment; filename=" + HttpUtility.UrlEncode(dt.Rows[0][1].ToString(), System.Text.Encoding.UTF8));
                    //指定文件类型
                    Response.ContentType = "application/octet-stream";
                    //Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");
                    Response.BinaryWrite(fileBytes);
                    Response.Flush();
                    Response.End();