Symfony2 form events and model transformers

Question

I\'m getting tied in knots trying to wrestle with Symfony2\'s form builders, events and transformers... hopefully somebody here is more experienced and can help out!

Answer 1

For anyone that is still looking for a better way to add/re-add a Model Transformer inside form events, I think that the best solution is the one from this post all credits go to @Toilal for this brilliant solution

So if you implement the ModelTransformerExtension and define it as a service, and change some code, for example, from

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->addEventListener(
            FormEvents::PRE_SET_DATA,
            array($this, 'onPreSetData')
        );
    $builder->add(
                $builder
                    ->create('customer', TextType::class, [
                        'required' => false,
                        'attr' => array('class' => 'form-control selectize-customer'),
                    ])
                    ->addModelTransformer(new CustomerToId($this->customerRepo))
            )
            ;
}

to something like:

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->addEventListener(
                FormEvents::PRE_SET_DATA,
                array($this, 'onPreSetData')
            );
    $builder->add('customer', TextType::class, [
                'required' => false,
                'attr' => array('class' => 'form-control selectize-customer'),
                'model_transformer' => new CustomerToId($this->customerRepo),
            ]
        )
        ;
}

And now if we remove and re-add the desired field inside the eventlistener function, the Model Transformer for the field will not be lost.

protected function onPreSetData(FormEvent $event)
{
    $form = $event->getForm();
    $formFields = $form->all();
    foreach ($formFields as $key=>$value){
        $config = $form->get($key)->getConfig();
        $type = get_class($config->getType()->getInnerType());
        $options = $config->getOptions();

        //you can make changes to options/type for every form field here if you want 

        if ($key == 'customer'){
            $form->remove($key);
            $form->add($key, $type, $options);
        }
    }
}

Note that this is a simple example. I've used this solution to easily process a form to have multiple field states in different places.