下载文件byte[]

    private void Download(string fileName, byte[] buffer)
    {
        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.AddHeader("Content-Length", buffer.Length.ToString());
        Response.BinaryWrite(buffer);
        Response.Flush();
        //Response.End();
    }