protected void btnGenerate_Click(object sender, EventArgs e)
    {
        // check 'EcommerceModify' permission
        if (!ECommerceContext.IsUserAuthorizedForPermission("ModifyOrders"))
        {
            RedirectToAccessDenied("CMS.Ecommerce", "EcommerceModify OR ModifyOrders");
        }

        // Save updated order invoice number
        //   order.OrderInvoiceNumber = txtInvoiceNumber.Text;
        order.SetValue("facture", txtInvoiceNumber.Text);
        OrderInfoProvider.SetOrderInfo(order);

        // Generate and display new invoice
        string invoice = OrderInfoProvider.GetInvoice(orderId);

        lblInvoice.Text = URLHelper.MakeLinksAbsolute(invoice);

        // Save new invoice
        order.OrderInvoice = invoice;
        OrderInfoProvider.SetOrderInfo(order);

        // Show message
        ShowChangesSaved();
    }