Symfony2 collection of choices different option for each elements - symfony

Question

After several search and try I don't know how to solve my problem.
I found this: Symfony2 Form Collection Field with Different Choices but solution was not given only a search trail and I didn't found how to adapt solution in my case.
I have Many to Many relation between Localization and Region, Many to Many relation between LOcalization and Department and Many to Many relation between Localization and City.
To create a localization i have this form:
class LocalizationType extends AbstractType{
private $manager;
public function __construct(ObjectManager $manager)
{
$this->manager = $manager;
}
public function buildForm(FormBuilderInterface $builder, array $options){
$builder->add('regions', CollectionType::class, array('entry_type' => ChoiceType::class,
'allow_add' => true,
'allow_delete' => true,
'required' => false,
'entry_options' => array(
'choices' => (array_key_exists('regions', $options['localization_value']) ? $options['localization_value']['regions'] : array('' => '')),
'multiple' => false,
'expanded' => false,
'attr' => array('class' => 'region input'),
),
'data' => (array_key_exists('regions', $options['localization_data']) ? $options['localization_data']['regions'] : null),
))
->add('departments', CollectionType::class, array('entry_type' => ChoiceType::class,
'allow_add' => true,
'allow_delete' => true,
'required' => false,
'entry_options' => array(
'choices' => (array_key_exists('departments', $options['localization_value']) ? $options['localization_value']['departments'] : array('' => '')),
'multiple' => false,
'expanded' => false,
'attr' => array('class' => 'department input')
),
'data' => (array_key_exists('departments', $options['localization_data']) ? $options['localization_data']['departments'] : null),
))
->add('cities', CollectionType::class, array('entry_type' => ChoiceType::class,
'allow_add' => true,
'allow_delete' => true,
'required' => false,
'entry_options' => array(
'choices' => (array_key_exists('cities', $options['localization_value']) ? $options['localization_value']['regions'] : array('' => '')),
'multiple' => false,
'expanded' => false,
'attr' => array('class' => 'city input')
),
'data' => (array_key_exists('cities', $options['localization_data']) ? $options['localization_data']['cities'] : null),
))
;
$builder->addEventListener(FormEvents::PRE_SUBMIT, function (FormEvent $event){
$data = $event->getData();
if(!empty($data['regions']) && is_array($data['regions'])){
$regions = array();
foreach($data['regions'] as $region){
$regions[] = $region;
}
$data['regions'] = $this->manager->getRepository('LocalizationBundle:Region')->findRegionsForCreateEntity($regions);
}
if(!empty($data['departments']) && is_array($data['departments'])){
$departments = array();
foreach($data['departments'] as $department){
$departments[] = $department;
}
$data['departments'] = $this->manager->getRepository('LocalizationBundle:Departments')->findDepartmentsForCreateEntity($departments);
}
if(!empty($data['cities']) && is_array($data['cities'])){
$cities = array();
foreach($data['cities'] as $city){
$cities[] = $city;
}
$data['cities'] = $this->manager->getRepository('LocalizationBundle:City')->findCitiesForCreateEntity($cities);
}
$form = $event->getForm();
$form->add('regions', CollectionType::class, array('entry_type' => ChoiceType::class,
'allow_add' => true,
'allow_delete' => true,
'required' => false,
'entry_options' => array(
'choices' => $data['regions'],
'multiple' => false,
'expanded' => false,
'attr' => array('class' => 'region input')
)
));
$form->add('departments', CollectionType::class, array('entry_type' => ChoiceType::class,
'allow_add' => true,
'allow_delete' => true,
'required' => false,
'entry_options' => array(
'choices' => $data['departments'],
'multiple' => false,
'expanded' => false,
'attr' => array('class' => 'department input')
)
))
->add('cities', CollectionType::class, array('entry_type' => ChoiceType::class,
'allow_add' => true,
'allow_delete' => true,
'required' => false,
'entry_options' => array(
'choices' => $data['cities'],
'multiple' => false,
'expanded' => false,
'attr' => array('class' => 'city input')
)
))
;
});
}
public function configureOptions(OptionsResolver $resolver){
$resolver->setDefaults(array(
'data_class' => Localization::class,
'localization_data' => array('regions' => '', 'departments' => '', 'cities' => ''),
'localization_value' => array('regions' => '', 'departments' => '', 'cities' => ''),
));
}
I choose a ChoiceType empty because I have several City for example( more of 25k) so I prefer load few of them with AJAX in my view and render them in a select2, it works for add action but for edit action I have a problem I want each field of my collections have a different value.
To illustrate my story, I want this result:
<label>Region n°1</label>
<select id="" name="">
<option value="foo1">bar1</option>
</select>
<label>Region n°2</label>
<select id="" name="">
<option value="foo2">bar2</option>
</select>
And the result I have for the moment is:
<label>0</label>
<select id="" name="">
<option value="foo1" selected="selected">bar1</option>
<option value="foo2">bar2</option>
</select>
<label>1</label>
<select id="" name="">
<option value="foo1">bar1</option>
<option value="foo2" selected="selected">bar2</option>
</select>
To change label if I understand I need to create my own template, ok but to display only option selected and not others I think I need a FormEventListener on PRE_SET_DATA but I don't see how implement this. So if someone has a solution, I'll take it.

Answer 1

I answer my own question, after try with FormEventListener on PRE_SET_DATA, on POST_SET_DATA, or with a choice_loader it's seems to be impossible to do what i want with a Symfony way, but i don't well understand why. I feel back on Jquery way to remove option who are not selected with following code, i dislike but I don't see others solutions:
<script type="text/javascript">
$.each($('.region'), function(i, val){
$(val).find('option:not(:selected)').remove();
})
$.each($('.department'), function(i, val){
$(val).find('option:not(:selected)').remove();
})
$.each($('.city'), function(i, val){
$(val).find('option:not(:selected)').remove();
})
</script>
I don't pass the topic as solved in case I'm wrong