public function isSortable() 
    {
        $this->getSearchCriteria();
        $sortable = new \stdClass;
        if($this->searchModel->Menu_id > 0) {
            $sortable->sortable = true;
            $sortable->link = Url::toRoute(['sort', 'Menu_id' => $this->searchModel->Menu_id]);
        } else {
            $sortable->sortable = false;
            $sortable->message = 'Filter on a menu first';
        }
        return $sortable;
    }