我有一个带有两层动态字段的Symfony2 Form。第一层在实现表单事件的文档化方式时没有问题：http://symfony.com/doc/current/cookbook/form/dynamic_form_modification.html#dynamic-生成提交的表单
但接下来是第三个场，它取决于第二个场，这已经是一个动态场了。
为了证明这个问题，这里是我的剥离代码：
<?php
class ServiceeventType extends AbstractType
{
/**
* @param FormBuilderInterface $builder
* @param array $options
*/
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('park', 'entity', array(
'class' => 'AppBundle:Park',
'property' => 'identifyingName',
'label' => 'Park',
'required' => true,
'invalid_message' => 'Choose a Park',
'placeholder' => 'Please choose',
))
// just a placeholder for the $builder->get('facility')->addEventListener to have something to bind to
// I'm aware, that this is just a symptom of my problem
->add('facility', 'choice', array(
'choices' => array(),
'expanded' => true,
'multiple' => false,
'label' => 'Facility',
'required' => false,
'invalid_message' => 'Choose a Park first',
'placeholder' => 'Please choose a Park first',
))
// other fields
;
$formModifierPark = function (FormInterface $form, Park $park = null) {
// overwrite the facility field with the desired entity type
$form->add('facility', 'entity', array(
'class' => 'AppBundle:Facility',
'property' => 'identifyingName',
'choices' => null === $park ? array() : $park->getFacilities(),
'label' => 'Facility',
'required' => true,
'invalid_message' => 'Choose a Facility',
'placeholder' => null === $park ? 'Please choose a Park first' : 'Please choose',
));
};
$formModifierFacility = function (FormInterface $form, Facility $facility = null) {
$form->add('facilityStatuscode', 'entity', array(
'class' => 'AppBundle:FacilityStatuscode',
'property' => 'identifyingName',
'choices' => null === $facility ? array() : $facility->getFacilityStatuscodeType()->getFacilityStatuscodes(),
'label' => 'Statuscode',
'required' => null === $facility ? false : true,
'invalid_message' => 'Choose a Statuscode',
'placeholder' => null === $facility ? 'Please choose a Facility first' : 'Please choose',
));
};
$builder->addEventListener(
FormEvents::PRE_SET_DATA,
function (FormEvent $event) use ($formModifierPark) {
$formModifierPark($event->getForm(), $event->getData()->getPark());
}
);
$builder->get('park')->addEventListener(
FormEvents::POST_SUBMIT,
function (FormEvent $event) use ($formModifierPark) {
$formModifierPark($event->getForm()->getParent(), $event->getForm()->getData());
}
);
$builder->addEventListener(
FormEvents::PRE_SET_DATA,
function (FormEvent $event) use ($formModifierFacility) {
$formModifierFacility($event->getForm(), $event->getData()->getFacility());
}
);
$builder->get('facility')->addEventListener(
FormEvents::POST_SUBMIT,
function (FormEvent $event) use ($formModifierFacility) {
$formModifierFacility($event->getForm()->getParent(), $event->getForm()->getData());
}
);
}
// more code
}
现在的问题是：
设置为$builder->get('facility')->addEventListener(FormEvents::POST_SUBMIT,…的事件侦听器此时丢失，设施字段被其他事件侦听器覆盖。
我尝试了几种解决方案，但事实证明，一旦构建器准备就绪（即在事件侦听器中添加时），表单字段选项就不能被覆盖，并且表单后来添加的字段不接受新的事件侦听器。
我真的必须解决这个问题。我是不是错过了什么？Symfony2的表单引擎是否无法处理两层动态表单字段依赖关系？
有什么建议吗？
感谢dmnptr第一条评论中的链接(http://showmethecode.es/php/symfony/symfony2-4-dependent-forms/)，我可以为我的案子解决这个问题。诀窍是，将事件绑定到整个表单，而不是绑定到某些字段（以及绑定到PRE_SUBMIT而不是POST_SUBMIT）。所以我的表单类现在看起来是这样的：
<?php
class ServiceeventType extends AbstractType
{
/**
* @param FormBuilderInterface $builder
* @param array $options
*/
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('park', 'entity', array(
'class' => 'AppBundle:Park',
'property' => 'identifyingName',
'label' => 'Park',
'required' => true,
'invalid_message' => 'Choose a Park',
'placeholder' => 'Please choose',
))
// other fields
;
$addFacilityForm = function (FormInterface $form, $park_id) {
// it would be easier to use a Park entity here,
// but it's not trivial to get it in the PRE_SUBMIT events
$form->add('facility', 'entity', array(
'class' => 'AppBundle:Facility',
'property' => 'identifyingName',
'label' => 'Facility',
'required' => true,
'invalid_message' => 'Choose a Facility',
'placeholder' => null === $park_id ? 'Please choose a Park first' : 'Please Choose',
'query_builder' => function (FacilityRepository $repository) use ($park_id) {
// this does the trick to get the right options
return $repository->createQueryBuilder('f')
->innerJoin('f.park', 'p')
->where('p.id = :park')
->setParameter('park', $park_id)
;
}
));
};
$builder->addEventListener(
FormEvents::PRE_SET_DATA,
function (FormEvent $event) use ($addFacilityForm) {
$park = $event->getData()->getPark();
$park_id = $park ? $park->getId() : null;
$addFacilityForm($event->getForm(), $park_id);
}
);
$builder->addEventListener(
FormEvents::PRE_SUBMIT,
function (FormEvent $event) use ($addFacilityForm) {
$data = $event->getData();
$park_id = array_key_exists('park', $data) ? $data['park'] : null;
$addFacilityForm($event->getForm(), $park_id);
}
);
$addFacilityStatuscodeForm = function (FormInterface $form, $facility_id) {
$form->add('facilityStatuscode', 'entity', array(
'class' => 'AppBundle:FacilityStatuscode',
'property' => 'identifyingName',
'label' => 'Statuscode',
'required' => true,
'invalid_message' => 'Choose a Statuscode',
'placeholder' => null === $facility_id ? 'Please choose a Facility first' : 'Please Chosse',
'query_builder' => function (FacilityStatuscodeRepository $repository) use ($facility_id) {
// a bit more complicated, that's how this model works
return $repository->createQueryBuilder('fs')
->innerJoin('fs.facilityStatuscodeType', 'fst')
->innerJoin('AppBundle:Facility', 'f', 'WITH', 'f.facilityStatuscodeType = fst.id')
->where('f.id = :facility_id')
->setParameter('facility_id', $facility_id)
;
}
));
};
$builder->addEventListener(
FormEvents::PRE_SET_DATA,
function (FormEvent $event) use ($addFacilityStatuscodeForm) {
$facility = $event->getData()->getFacility();
$facility_id = $facility ? $facility->getId() : null;
$addFacilityStatuscodeForm($event->getForm(), $facility_id);
}
);
$builder->addEventListener(
FormEvents::PRE_SUBMIT,
function (FormEvent $event) use ($addFacilityStatuscodeForm) {
$data = $event->getData();
$facility_id = array_key_exists('facility', $data) ? $data['facility'] : null;
$addFacilityStatuscodeForm($event->getForm(), $facility_id);
}
);
}
// more code
}
AJAX的工作原理与上的文章链接中建议的一样