ext grid 中怎样显示ComboBox

{ header: "所属供应商", width: 150, dataIndex : 'purveyModuleId' ,  editor: purveyModuleId,renderer: function(v){
	var rec = this.editor.getStore().getAt(v);
		if (rec == null) {
			return v;
		} else {
			return rec.data[this.editor.displayField];
	}
}},