public function actionIndex($parent_id = 1)
{
$searchModel = new Navigation(['scenario' => 'search']);
$searchModel->parent_id = $parent_id;
$dataProvider = $searchModel->search($_GET);
$model = null;
if ($parent_id > 0) {
$model = Navigation::findOne($parent_id);
}
return $this->render('index', ['dataProvider' => $dataProvider, 'searchModel' => $searchModel, 'model' => $model]);
}