Nested Symfony2 Forms: $options['data'] = null in nested form? - php

Question

As the documentation around this topic is somewhat thin, I got to a dead end.
I have two models: Job and JobAttribute.
A Job has many JobAttributes and a JobAttribute has one Job:
class Job {
/**
* #ORM\OneToMany(targetEntity="JobAttribute", mappedBy="job_attributes")
*
* #var ArrayCollection
*/
private $attributes;
}
class JobAttribute {
/**
* #ORM\Column(name="type", type="string", length=50)
*
* #var string
*/
private $type;
/**
* #ORM\ManyToOne(targetEntity="Job", inversedBy="jobs")
*/
private $job;
Now,I have the following FormClass:
class JobType extends AbstractType {
public function buildForm(FormBuilder $f, array $options) {
$f->add('name', 'text');
$f->add('attributes', 'collection', array('type' => new JobAttributeType()));
}
public function getName() {
return 'job';
}
}
class JobAttributeType extends AbstractType {
public function buildForm(FormBuilder $f, array $options) {
$attribute = $options['data'];
$f->add('value', $attribute->getType());
}
public function getDefaultOptions(array $options) {
return array('data_class' => 'JWF\WorkflowBundle\Entity\JobAttribute');
}
public function getName() {
return 'job_attribute';
}
}
Yes, indeed, the type property of JobAttribute contains a Form field type, eg. text.
So, as I call a FormBuilder on JobType in my Controller, $options['data'] is correctly populated with a Job-Object within JobType.
But the nested JobAttributeType's $options['data'] doesn't point to an JobAttribute object. It's NULL.
What's the problem? Where is the association lost? Why is $options['data'] = NULL in nested forms?
Is there a workaround in order to get dynamic field types (out of Doctrine) in a nested form?
Thanks in advance!

Answer 1

You cannot rely on $options['data'] when you build the form, as the data can (and will) be changed anytime after building. You should use event listeners instead.
$formFactory = $builder->getFormFactory();
$builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event) use ($formFactory) {
$form = $event->getForm();
$data = $event->getData();
if ($data instanceof JobAttribute) {
$form->add($formFactory->createNamed('value', $data->getType());
}
});
The documentation for this can be found in the cookbook.