Symfony6中的级联动态添加字段

Question

我有一个表格，上面有三个下拉选项：

FieldA FieldB FieldC

FieldB的选择依赖于fieldA的选择，FieldC的选择依赖于fieldB的选择

这些关系是：

EntityB ManyToMany EntityA

EntityC ManyToOne EntityB

一切正常，说明提交表单无效，错误是“此表单不应包含额外字段”，罪魁祸首是fieldC。

我做错什么了？

下面是我的FormType代码：

    public function buildForm(FormBuilderInterface $builder, array $options): void
    {
        $builder
            ->add('fieldA', EntityType::class, [
                'class' => EntityA::class,
                'choice_label' => 'name',
                'query_builder' => function(EntityARepository $a) {
                    return $a->createQueryBuilder('a')
                        ->orderBy('a.name', 'ASC');
                },
            ])

        ;

        $builder->get('fieldA')->addEventListener(
          FormEvents::POST_SUBMIT,
          function(FormEvent $event) {
              $form = $event->getForm();
              $this->setupFieldB(
                  $form->getParent(),
                  $form->getData()
              );
          }
        );

        $builder->addEventListener(
            FormEvents::PRE_SET_DATA,
            function(FormEvent $event) {
                $data = $event->getData();
                if (!$data or !isset($data['fieldA'])) {
                    return;
                }
                $this->setupFieldB(
                    $event->getForm(),
                    $data['fieldA']
                );
            }
        );

        if ($builder->has('fieldB')) {
            $builder->get('fieldB')->addEventListener(
                FormEvents::POST_SUBMIT,
                function (FormEvent $event) {
                    $form = $event->getForm();
                    $this->setupFieldC(
                        $form->getParent(),
                        $form->getData()
                    );
                }
            );
        }

        $builder->addEventListener(
            FormEvents::PRE_SET_DATA,
            function (FormEvent $event) {
                $data = $event->getData();
                if (!$data or !isset($data['fieldB'])) {
                    return;
                }
                $this->setupFieldC(
                    $event->getForm(),
                    $data['fieldB']
                );
            }
        );
    }

    private function setupFieldB(FormInterface $form, ?string $selectedfieldA)
    {
        if (is_null($selectedfieldA)) {
            $form->remove('fieldB');
            $form->remove('fieldC');
            return;
        } else {
            $fieldA = $this->EntityARepository->findOneBy(['name' => $selectedfieldA]);
            $form
                ->add('fieldB', EntityType::class, [
                    'class' => EntityB::class,
                    'query_builder' => function (EntityBRepository $b) use ($fieldA) {
                        return $b->createQueryBuilder('b')
                            ->andWhere(':fieldA MEMBER of b.fieldAs')
                            ->setParameter('fieldA', $fieldA)
                            ->orderBy('b.name', 'ASC');
                    },
                    'choice_label' => 'name',
                ]);
        }
    }

    private function setupFieldC(FormInterface $form, ?string $selectedFieldB)
    {
        if (is_null($selectedFieldB)) {
            $form->remove('fieldC');
            return;
        } else {
            $fieldB = $this->fieldBRepository->findOneBy(['name' => $selectedFieldB]);
            $form
                ->add('fieldC', EntityType::class, [
                    'class' => EntityC::class,
                    'query_builder' => function(EntityCRepository $c) use ($fieldB) {
                        return $c->getQueryBuilderWithFilter(['fieldB' => $fieldB]);
                    },
                    'choice_label' => 'name',
                ]);
        }
    }

Answer 1

经过进一步的研究，我找到了以下解决方案：

( a)用if ($builder->has('fieldB')) {删除该部分--因为这始终被解析为false。

( b)重写函数setupFieldB .如下所示：

private function setupFieldB(FormInterface $form, ?string $selectedfieldA)
{
    if (is_null($selectedfieldA)) {
        $form->remove('fieldB');
        $form->remove('fieldC');
        return;
    } else {
        $fieldA = $this->EntityARepository->findOneBy(['name' => $selectedfieldA]);
        
        $newBuilder = $form->getConfig()->getFormFactory()->createNamedBuilder('fieldB', 
            EntityType::class, null, [
                'class' => EntityB::class,
                'query_builder' => function (EntityBRepository $b) use ($fieldA) {
                    return $b->createQueryBuilder('b')
                        ->andWhere(':fieldA MEMBER of b.fieldAs')
                        ->setParameter('fieldA', $fieldA)
                        ->orderBy('b.name', 'ASC');
                },
                'choice_label' => 'name',
            ]);
        
        // now we can add the listener:
        $newBuilder->addEventListener(FormEvents::POST_SUBMIT, function (FormEvent $event) {
            $form = $event->getForm();
            $this->setupFieldC(
                $form->getParent(),
                $form->getData()
            );
        });
        
        // finally add the field to the form
        $form->add($newBuilder->getForm());
    }
}