我最近在學(xué)習(xí) Symfony。我遇到了一個(gè)錯(cuò)誤，我打電話時(shí)找不到認(rèn)真的答案。錯(cuò)誤是這樣的： 未捕獲的PHP 異常 Symfony \ Component \ PropertyAccess \ Exception \ InvalidArgumentException：“類型的預(yù)期參數(shù)”int或null“，”對(duì)象“在屬性路徑”parent_id“?！?在 /home/vagrant/code/vendor/symfony/property-access/PropertyAccessor.php 第 198 行我的控制器文件中有這些代碼：public function new(Request $request): Response{    $category = new Category();    $form = $this->createForm(CategoryType::class, $category);    $form->handleRequest($request);    if ($form->isSubmitted() && $form->isValid()) {        $entityManager = $this->getDoctrine()->getManager();        $entityManager->persist($category);        $entityManager->flush();        return $this->redirectToRoute('category_index');    }    return $this->render('category/new.html.twig', [        'category' => $category,        'form' => $form->createView(),    ]);}我的 FormType 文件如下所示：<?phpnamespace App\Form;use App\Entity\Category;use Symfony\Bridge\Doctrine\Form\Type\EntityType;use Symfony\Component\Form\AbstractType;use Symfony\Component\Form\FormBuilderInterface;use Symfony\Component\OptionsResolver\OptionsResolver;class CategoryType extends AbstractType{    public function buildForm(FormBuilderInterface $builder, array $options)    {        $builder            ->add('name', null, [                'attr' => ['class' => 'form-control'],            ])            ->add('slug', null, [                'attr' => ['class' => 'form-control'],            ])            ->add('parent_id', EntityType::class, [                'class' => Category::class,                'choice_label' => 'name',                'attr' => ['class' => 'form-control'],                'placeholder' => 'üst Kategori Se?iniz',            ])            ->add('title', null, [                'attr' => ['class' => 'form-control']            ])            ->add('description', null, [                'attr' => ['class' => 'form-control']            ])        ;    }