dgtKalemler.headers[10] = new dgtblHeader({ id: 10, text: "Açıklama", dataField: "aciklama", template: tmpAciklama1 });
        **dgtKalemler.headers[11] = new dgtblHeader({ id: 11, text: "Koli İçi Paket Miktarı", dataField: "kutu",validationRules: [{ type: 'required' }], template: tmpKutu });**
        dgtKalemler.headers[15] = new dgtblHeader({ id: 15, text: "Termin Tarihi", dataField: "testarih", template: tmpTerminTarihi, dataType: TYPE_DATE });

I can't make the text field required, may be i am trying wrong. How can I make it (gtKalemler.headers[15]) required ?