Child in Form Collection not submitted - symfony

Question

I have a form with a collection field. When I submit the parent form, children added in the collection field are not submitted.
Here is what the Profiler says :
Request/Response tab :
I added a child in creneaux collection but as you can see, there isn't any child submitted in creneaux.
I don't have any error in the submitted form though.
I can't find where I'm mistaken.
Parent form :
class MiseEnLigneFormType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder->add('nom', TextType::class, ['label' => 'Titre'])
->add('tempsEpreuve', TimeType::class,
['label' => 'Durée',
'label_attr' => ['class' => 'active'],
'required' => true,
'widget' => 'single_text'])
->add('creneaux', CollectionType::class,
['label' => false,
'label_attr' => ['class' => 'active'],
'entry_type' => CreneauFormType::class,
'allow_add' => true,
'allow_delete' => true,
'by_reference' => false
])
->add('polycopies', CollectionType::class,
['label' => false,
'label_attr' => ['class' => 'active'],
'entry_type' => PolycopieFormType::class,
'allow_add' => true,
'allow_delete' => true,
'by_reference' => false
]);
}
Child form :
class CreneauFormType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder->add('dateDebut', DateTimeType::class, ['label' =>'Début',
'label_attr' => ['class'=>'active'],
'format' => 'dd-MM-yyyy HH:mm',
'widget' => 'single_text',
'attr' => ['data-field'=>'datetime']])
->add('dateFin', DateTimeType::class, ['label' => 'Fin',
'label_attr' => ['class'=>'active'],
'format' => 'dd-MM-yyyy HH:mm',
'widget' => 'single_text',
'attr' => ['data-field'=>'datetime']])
->add('test', CheckboxType::class, ['label' => false, 'required' => false]);
}
Controller :
$originalCreneaux = new ArrayCollection();
foreach ($colle->getCreneaux() as $creneau) {
$originalCreneaux->add($creneau);
}
$form = $this->createForm(MiseEnLigneFormType::class, $colle);
$form->handleRequest($request);
if ($form->isSubmitted()) {
if ($form->isValid()) {
return $this->render('Creneau/edit.html.twig', ['form' => $form->createView(),
'colle' => $colle,
'matiereName' => $matiereName]);
}
}
Twig :
{{ form_start(form) }}
<div class="card card-content">
{{ form_widget(form.nom) }}
{{ form_label(form.nom) }}
{{ form_widget(form.tempsEpreuve) }}
{{ form_label(form.tempsEpreuve) }}
</div>
<div class="card card-content">
<table class="polycopies centered"
data-prototype="{{ form_widget(form.polycopies.vars.prototype)|e }}">
<thead>
<tr>
<th>Nom</th>
<th>Supprimer</th>
</tr>
</thead>
<tbody class="poly_body">
{% for poly in form.polycopies %}
<tr>
<td>
{{ form_widget(poly.nom) }}
{{ form_label(poly.nom) }}
</td>
<td>
<a href="" class="delete_poly_link">
<i class="material-icons">delete</i>
</a>
</td>
</tr>
{% endfor %}
</tbody>
</table>
<div class="" id="liensAjouterPolycopies">
<a href="" class="add_poly_link btn-flat" data-tooltip="Ajouter un polycopié">
<i class="material-icons">add</i>Ajouter un polycopié
</a>
</div>
<div class="card card-content">
<span class="card-title">Créneaux</span>
<table class="creneaux centered"
data-prototype="{{ form_widget(form.creneaux.vars.prototype)|e }}">
<thead>
<tr>
<th>Date de début</th>
<th>Date de fin</th>
<th>Test</th>
<th>Supprimer</th>
</tr>
</thead>
<tbody class="creneau_body">
{% for creneau in form.creneaux %}
<tr>
<td class="center-align">
{{ form_widget(creneau.dateDebut) }}
{{ form_label(creneau.dateDebut) }}
</td>
<td class="center-align">
{{ form_widget(creneau.dateFin) }}
{{ form_label(creneau.dateFin) }}
</td>
<td class="center-align">
{{ form_widget(creneau.test) }}
{{ form_label(creneau.test) }}
</td>
<td class="center-align">
<a href="" class="delete_creneau_link">
<i class="material-icons">delete</i>
</a>
</td>
</tr>
{% endfor %}
</tbody>
</table>
{{ form_rest(form) }}
</div>
<button class="btn-large fullwidth" type="submit" value="Sauvegarder">
<i class="material-icons left">save</i>
Enregistrer
</button>
{{ form_end(form) }}
<script>
var collectionHolder = $('table.creneaux');
var num = $('.creneau_body').children().length + 1;
jQuery(document).ready(function () {
$(document).on("click", "a.add_creneau_link", function (e) {
e.preventDefault();
addCreneauForm(collectionHolder);
return false;
});
$(document).on("click","a.delete_creneau_link", function () {
var $this = $(this);
$this.closest('tr').remove();
return false;
});
function addCreneauForm(collectionHolder) {
var prototype = collectionHolder.attr('data-prototype');
var newForm = prototype.replace(/__name__/g, num);
num += 1;
$tableau = newForm.split("<div>");
var form = '';
for (var i = 1; i < $tableau.length; i++) {
form += "<td class='center-align'>" + $tableau[i] + "</td>";
}
form += "<td class='center-align'><a href='' class='delete_creneau_link'><i class='material-icons'>delete</i></a></td>";
var $form = $('<tr></tr>').append(form);
$form.insertAfter('.creneaux tr:last');
}
</script>

Answer 1

There is no persist nor flush after the submit event
$entityManager = $this->getDoctrine()->getManager();
$entityManager->persist($creneau);
$entityManager->flush();
Did you accidently forget ?