如何从Data Transformer对象类内部为请求使用DoctrineParamConverter？

use Doctrine\ORM\EntityManagerInterface;
use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Form\Exception\TransformationFailedException;

class EntityToIdTransformer implements DataTransformerInterface
{
    private $entityManager;
    private $entityClass;

    public function __construct(EntityManagerInterface $entityManager, string $entityClass)
    {
        $this->entityManager = $entityManager;
        $this->entityClass = $entityClass;
    }

    public function transform($entity)
    {
        if (null === $entity) {
            return '';
        }

        return $entity->getId();
    }

    public function reverseTransform($id)
    {
        if (!$id) {
            return null;
        }

        $entity = $this->entityManager
            ->getRepository($this->entityClass)
            ->find($id);

        if (null === $entity) {
            throw new TransformationFailedException(sprintf(
                'The entity with id "%s" does not exist!',
                $id
            ));
        }

        return $entity;
    }
}

use App\Form\Type\YourFormType;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\Annotation\Route;

class YourController extends AbstractController
{
    /**
     * @Route("/your-route", name="your_route")
     */
    public function yourAction(Request $request)
    {
        $entityManager = $this->getDoctrine()->getManager();

        $form = $this->createForm(YourFormType::class);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            // 获取转换后的实体对象
            $entity = $form->getData();

            // 执行其他操作，如保存实体对象到数据库

            return $this->redirectToRoute('success_route');
        }

        return $this->render('your_template.html.twig', [
            'form' => $form->createView(),
        ]);
    }
}

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\FormBuilderInterface;

class YourFormType extends AbstractType
{
    private $entityManager;

    public function __construct(EntityManagerInterface $entityManager)
    {
        $this->entityManager = $entityManager;
    }

    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('entity', TextType::class, [
                'label' => 'Entity',
                'required' => true,
            ])
            ->get('entity')
            ->addModelTransformer(new EntityToIdTransformer($this->entityManager, YourEntity::class));
    }
}