文件下载防文件名乱码

 Response.ContentType = "application/vnd.ms-excel";
            Response.AddHeader("Content-Disposition", string.Format("attachment;filename={0}", HttpUtility.UrlEncode(execlName)  + DateTime.Now.ToString("yyyy-MM-dd").Trim() + ".xls"));
            Response.Clear();
            excel.WriteTo(Response.OutputStream);
            Response.End();

HttpUtility.UrlEncode(execlName) //防文件名乱码