IenumDynamicToExcelHandler

        public void ProcessRequest(HttpContext context)
        {
            context.Response.Clear();
            context.Response.ContentType = "application/force-download";
            context.Response.AddHeader("content-disposition", "attachment; filename=Current-OptIns_" + DateTime.UtcNow.ToString("yyyyMMddHHmm") + "utc.xls");
            
            List<ExpandoObject> optInList = DbServices.GetCurrentOptIns(optInList);
            DataTable dt = optInList.ToDataTable();
            GridView gv = new GridView();
            gv.DataSource = dt;
            gv.DataBind();

            var sw = new StringWriter();
            var writer = new HtmlTextWriter(sw);
            gv.RenderControl(writer);
            context.Response.Write(sw.ToString());

            context.Response.End();
        }