Symfony transform ChoiceType in CheckboxType - php

Question

I've problem with my form type. I have an entity activity and an other entity class. It's in ManyToMany. When I display the form, it's in ChoiceType, but I want it to be in CheckboxType. So I've :
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder->add('libelle')
->add('horraire')
->add('horraireDebut')
->add('horraireFin')
->add('description')
->add('classes');
}
It display a ChoiceType but I want a CheckboxType, so I changed this to :
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder->add('libelle')
->add('horraire')
->add('horraireDebut')
->add('horraireFin')
->add('description')
->add('classes', CheckboxType::class);
}
But this only displays one checkbox while I have several recordings (which appears well with the first code).
My form.html.twig :
<div class="form-group{% if form.classes.vars.errors|length %} has-error{% endif %}">
<label for="{{ form.classes.vars.id }}" class="col-sm-3 control-label no-padding-right required">Classes <span class="red">*</span></label>
<div class="col-sm-9">
{{ form_widget(form.classes,{'attr': {'class': 'form-control'}}) }}
{{ form_errors(form.classes) }}
</div>
How can I get a checkbox line or a checkbox dropdown ?
Thanks!

Answer 1

Just use multiple and expanded options together to achieve this (Ref):
$builder->add('classes', null, array(
'multiple' => true,
'expanded' => true,
));
Then checkboxes will be rendered.
Note that null value mean EntityType::class in case you use Doctrine ORM. Otherwise, use EntityType::class and 'class' => Entity::class option.

Answer 2

In order to achieve what you're looking for, you could also try the EntityType with a query builder:
->add('classes', EntityType::class, array(
'by_reference' => true,
'multiple' => true,
'expanded' => false,
'class' => 'AppBundle\Entity\Class',
'property' => 'name',
'query_builder' => function(\Doctrine\ORM\EntityRepository $er) {
$qb = $er->createQueryBuilder('c');
return $qb->orderBy('c.name', 'ASC');
}
))