Validate a dynamically populated choice field

Question

I've got two choice fields, one depending on the other.

When building the form the depending field got an empty choices' array.

I then fill this field in JavaScript requesting some datas from an action.

The issue comes from validation. Of course it doesn't pass because single or multiples values can't be valid against empty value. To solve that I've created a PRE_BIND listener which basically remove then recreate the choice field with the right values, but it still doesn't pass validation.

$form->getErrors() returns nothing but $form->getErrorsAsString() returns me an error on my choice field.

My form:

<?php

namespace Foo\BarBundle\Form\Type;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\Form\FormEvent;
use Symfony\Component\Form\FormEvents;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;

class BarFormType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        // other fields

        // This field is filled in ajax
        $builder->add('stores', 'choice', array(
            'label' => 'form.label.stores',
            'translation_domain' => 'FooBarBundle',
            'choices' => $options['storesList'],
            'required' => false,
            'multiple' => true,
            'auto_initialize' => false,
            'attr' => array(
                'class' => 'chzn-select',
                'placeholder' => 'form.placeholder.stores'
        )));

        $func = function (FormEvent $e) use ($options) {
            $data = $e->getData();
            $form = $e->getForm();
            if ($form->has('stores')) {
                $form->remove('stores');
            }

            $brand = isset($data['brand']) ? $data['brand'] : null;

            if ($brand !== null) {
                $choices = $options['miscRepo']->getStoresNameIndexedById($brand);
                $choices = array_keys($choices);
                $choices = array_map('strval', $choices);
            } else {
                $choices = array();
            }

            $form->add('stores', 'choice', array('choices' => $choices, 'multiple' => true, 'attr' => array('class' => 'chzn-select')));
        };

        $builder->addEventListener(FormEvents::PRE_SUBMIT, $func);
    }

    public function getName()
    {
        return 'bar_form_campaign';
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setRequired(array(
            'storesList',
            'miscRepo',
        ));
    }
}

Answer 1

I had the same issue like yours: updating a field via javascript, but didn't pass the validation. On PRE_SUBMIT event, read the value that you added with javascript, query and get the object with that ID, and update the field choices.

$builder->addEventListener(FormEvents::PRE_SUBMIT, function (FormEvent $event) {
    $data = $event->getData();
    $form = $event->getForm();
    $pageId = $data['page_id'];

    $page = $this->myManager->getPage($pageId);
    $options = array($page->getId() => $page->getTitle());

    $form->add('page_id', 'choice', array(
        'label'         => 'Select page',
        'choices'       => $options,
        'required'      => true,
        'placeholder'   => 'Select page'
    ));

    $form->getData()->setPageId($pageId);
});