我制作了一个表单，以便在选择用户时，其角色从[“ROLE_USER”]更改为[“ROLE_ADMIN”]。提交表单时，出现以下错误：Can't get a way to read the property "user" in class "App\Entity\User".
我知道这肯定是因为User类中没有名为user的字段，但我不知道用哪个字段替换user。我已经尝试了name或roles，但它们都不起作用。
如何选择用户并简单地更改其角色？

管理类型.php

<?php

namespace App\Form\Admin;

use App\Entity\User;
use Doctrine\ORM\EntityRepository;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Bridge\Doctrine\Form\Type\EntityType;
use Symfony\Component\OptionsResolver\OptionsResolver;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;

class AdminType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options): void
    {
        $builder
            ->add('user', EntityType::class, [
                'class' => User::class,
                'choice_label' => 'name',
                'query_builder' => function (EntityRepository $er) {
                    return $er->createQueryBuilder('u')
                        ->andWhere('u.roles LIKE :role')
                        ->setParameter('role', '["ROLE_USER"]')
                        ->orderBy('u.firstname', 'ASC');
                },
                'placeholder' => 'J\'ajoute un administrateur',
            ])
            ->add('save', SubmitType::class, [
                'attr' => ['class' => 'save'],
            ])
        ;
    }

    public function configureOptions(OptionsResolver $resolver): void
    {
        $resolver->setDefaults([
            'data_class' => User::class,
            'translation_domain' => 'forms'
        ]);
    }
}

管理控制器.php

<?php

namespace App\Controller\Admin;

use App\Form\Admin\AdminType;
use App\Repository\UserRepository;
use Doctrine\ORM\EntityManagerInterface;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\Annotation\Route;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;

class AdminController extends AbstractController
{
    #[Route('/admin/list', name: 'admin')]
    public function admin(
        Request $request, 
        UserRepository $userRepository,
        EntityManagerInterface $entityManagerInterface
    ){   
        $admins = $userRepository->admin();
        
        $form = $this->createForm(AdminType::class);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            $user = $form->get('user')->getData();
            $user->setRoles(["ROLE_ADMIN"]);

            $entityManagerInterface->persist($user);
            $entityManagerInterface->flush();

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

        return $this->renderForm('admin/user/admin.html.twig', [
            'admins' => $admins,
            'form' => $form
        ]);
    }