如何导出父子devexpress gridview到excell？

Question

我无法将父级devexpress gridview导出到excell

这是我尝试的

protected void Page_Load(object sender, EventArgs e)
        {
            CompId = Convert.ToInt32(Request.Cookies["LoginCookies"]["CompId"].ToString());

            BindSales();
        }
        protected void UpdateExportMode()
        {
            gvSales.SettingsDetail.ExportMode = (GridViewDetailExportMode)Enum.Parse(typeof(GridViewDetailExportMode), "Expanded");
        }

        protected void btnXLexp_Click(object sender, EventArgs e)
        {
            UpdateExportMode();
            Exporter.WriteXlsToResponse();
        }