筛选数据的数据小部件Yii2

我使用数据小部件与pjux和需要排序我的日期。我试着用这个http://www.yiiframework.com/doc-2.0/guide-output-data-widgets.html。但在过滤方面有困难。我SiteController

$PostView = Posts::findOne($id);
$model = new Comments();
if ($model->load(Yii::$app->request->post()) && $model->validate()) {
    $model->user_id = Yii::$app->user->getId();
    $model->post_id = $id;
    if ($model->save()):
        $model = new Comments();
        Yii::$app->session->setFlash('success', "OK");
    else: Yii::$app->session->setFlash('error', "NOT");
        Yii::error('Some error');
        return $this->refresh();
    endif;
} else {
    $searchModel = new CommentsSearch();
    $dataProvider = $searchModel->search(Yii::$app->request->queryParams);
    return $this->render('view', [
        'PostView' => $PostView,
        'searchModel' => $searchModel,
        'dataProvider' => $dataProvider,
        'model' => $model,
    ]);
}

我的搜索控制器

$query->andFilterWhere([
        'id' => $this->id,
        'post_id' => $this->post_id,
        'user_id' => $this->user_id,
        'created_at' => $this->created_at,
        'updated_at' => $this->updated_at,
    ]);
$query->andFilterWhere(['like', 'comment', $this->comment]);
return $dataProvider;

<?php Pjax::begin(['id' => 'comments']) ?>
<?= GridView::widget([
    'dataProvider' => $dataProvider,
    'filterModel' => $searchModel,
    'columns' => [
        ['class' => 'yii'grid'SerialColumn'],
        'post_id',
        'comment:ntext',
    ],
]); ?>
<?php Pjax::end() ?>

同样，如果我改变'post_id' => $this->post_id,对'post_id' => '1',过滤工作。请帮助。