public function listAction(Request $request)
 {
     $filterForm = $this->crud->createFilterFromRequest($request);
     $criteria = $this->crud->createCriteriaByFilter($filterForm, $request);
     $collection = $this->crud->getObjectCollection($criteria);
     $datagrid = $this->crud->createDatagrid($criteria, $collection);
     return $this->render($this->crud->getTemplate('list'), array('action' => 'list', 'crud' => $this->crud, 'datagrid' => $datagrid));
 }