protected void Page_Load(object sender, EventArgs e)
        {
            //Page.RegisterClientScript(typeof(Masters.ClientScripts.ListInvoiceViewData));

            if (UrlParameters.Action != "export")
            {
                RegisterScript();
            }
            else // export to csv
            {
                var invoiceItems = GetInvoiceItemsByFilter();

                if (invoiceItems.Count != 0)
                {
                    if (UrlParameters.View != "editor")
                    {
                        Response.Clear();
                        Response.ContentType     = "text/csv; charset=utf-8";
                        Response.ContentEncoding = Encoding.UTF8;
                        Response.Charset         = Encoding.UTF8.WebName;

                        var fileName = "products_services.csv";

                        Response.AppendHeader("Content-Disposition", String.Format("attachment; filename={0}", fileName));
                        Response.Write(ExportToCSV.ExportInvoiceItemsToCSV(invoiceItems, false));
                        Response.End();
                    }
                    else
                    {
                        var fileUrl = ExportToCSV.ExportInvoiceItemsToCSV(invoiceItems, true);
                        Response.Redirect(fileUrl);
                    }
                }
                else
                {
                    var cookie = HttpContext.Current.Request.Cookies.Get(ExportErrorCookieKey);
                    if (cookie == null)
                    {
                        cookie       = new HttpCookie(ExportErrorCookieKey);
                        cookie.Value = CRMSettingResource.ExportInvoiceItemsEmptyError;
                        HttpContext.Current.Response.Cookies.Add(cookie);
                    }
                    Response.Redirect(PathProvider.StartURL() + "settings.aspx?type=invoice_items");
                }
            }
        }