它将不显示默认选择值在我的多选下拉列表和我没有得到这mistak.is下拉列表接受数组为默认选择数组列表

public function actionCreate()
{
    .......
        $cust= implode('_',$_POST['supplier'] ['manufacture']);
        $model->customer = $cust;
        $model->save();
    ........
}
public function actionUpdate($id)
{
    $model = $this->findModel($id);
    $model->customer  = explode('_',$model->customer);
    if ($model->load(Yii::$app->request->post())) {
      $cust= implode(',',$_POST['supplier']['manufacturer']);
        $model->customer = $cust`enter code here`;
        $model->save();
        return $this->redirect(['view', 'id' => $model->ID]);
    } else {
        return $this->render('update', [
            'model' => $model,
        ]);
    }
}

查看

<?= 
$form->field($model, 'car_manufacturer[]')->dropDownList($model->getcustinfo(), [
    'multiple'=>'multiple',
    'class'=>'chosen-select input-md required',
    ]);
?>