drop down datamanager with parameters error

[Manolo]

Hi,

I've this page:



When I click on "Validar" button, I show a modal form, and this modal form has a drop downlist. When I click in any button the first time, I've get an error. After, works perfect.



My Javascript code:

 function onClick(args) {
        var grid = $("#gridPendientesValidar").ejGrid("instance");
        var index = this.element.closest("tr").index();
        var record = grid.getCurrentViewData()[index];

        $(".modal-body .hiddenId").val(record["ID"]);
        $(".modal-body .hiddenIdTipologia").val(record["IdTipologia"]);
        $(".modal-body .hiddenUserNameRemitente").val(record["RemitenteEnviado"]);

        var idTipologia = parseInt(record["IdTipologia"]);

        var dataManagerSubtipologias = ej.DataManager({
            url: baseUrl + "Notificaciones/GetSubtipologias",
            adaptor: new ej.UrlAdaptor(),           
        });
        $("#ddlSubtipologia").ejDropDownList({
            dataSource: dataManagerSubtipologias,
            query: new ej.Query().addParams("idTipologia", idTipologia),
            fields: { text: "Nombre", value: "IdSubtipologia" },
        });

       $("#modalValidacion").modal();

    }

My controller code

 public JsonResult GetSubtipologias(int idTipologia)
        {
            ////if (idTipologia == null)
            ////    return null;
            var datos = _repositorio.GetSubTipologias((int)idTipologia);
            return Json(datos);
        }

If i set as parameter int? the first time not work