Passing data to buildForm() in Symfony 2.8, 3.0 and above

Question

My application currently passes data to my form type using the constructor, as recommended in this answer. However the Symfony 2.8 upgrade guide advises that passing a type instance to the createForm function is deprecated:

Passing type instances to Form::add(), FormBuilder::add() and the FormFactory::create*() methods is deprecated and will not be supported anymore in Symfony 3.0. Pass the fully-qualified class name of the type instead.

Before:    
$form = $this->createForm(new MyType());

After:
$form = $this->createForm(MyType::class);

Seeing as I can't pass data through with the fully-qualified class name, is there an alternative?

Answer 1

This broke some of our forms as well. I fixed it by passing the custom data through the options resolver.

In your form type:

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $this->traitChoices = $options['trait_choices'];

    $builder
        ...
        ->add('figure_type', ChoiceType::class, [
            'choices' => $this->traitChoices,
        ])
        ...
    ;
}

public function configureOptions(OptionsResolver $resolver)
{
    $resolver->setDefaults([
        'trait_choices' => null,
    ]);
}

Then when you create the form in your controller, pass it in as an option instead of in the constructor:

$form = $this->createForm(ProfileEditType::class, $profile, [
    'trait_choices' => $traitChoices,
]);

Answer 2

Here's how to pass the data to an embedded form for anyone using Symfony 3. First do exactly what @sekl outlined above and then do the following:

In your primary FormType

Pass the var to the embedded form using 'entry_options'

->add('your_embedded_field', CollectionType::class, array(
          'entry_type' => YourEntityType::class,
          'entry_options' => array(
            'var' => $this->var
          )))

In your Embedded FormType

Add the option to the optionsResolver

public function configureOptions(OptionsResolver $resolver)
{
    $resolver->setDefaults(array(
        'data_class' => 'Yourbundle\Entity\YourEntity',
        'var' => null
    ));
}

Access the variable in your buildForm function. Remember to set this variable before the builder function. In my case I needed to filter options based on a specific ID.

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $this->var = $options['var'];

    $builder
        ->add('your_field', EntityType::class, array(
          'class' => 'YourBundle:YourClass',
          'query_builder' => function ($er) {
              return $er->createQueryBuilder('u')
                ->join('u.entity', 'up')
                ->where('up.id = :var')
                ->setParameter("var", $this->var);
           }))
     ;
}