Question

My form as field users (entity type). How can i add validation in order to specificity that at least one user should be selected? Actually i’m adding an event listener but i don’t know if this is a legit solution or not:

public function buildForm(\Symfony\Component\Form\FormBuilder $builder,
    array $options)
{
    $builder
        ->add('title', 'text', array(
            'label' => 'Titolo'
        ))
        ->add('content',  'textarea', array(
            'label' => 'Contenuto'
        ))
        ->add('sender_text',  'text', array(
            'label' => 'Mittente testuale',
        ))
        ->add('users', 'entity', array(
            'label'    => 'Destinatari',
            'class'    => 'DL\FidelityBundle\Entity\User',
            'property' => 'select_label',
            'multiple' => true
        ));
    ;

    // Valida il numero di utenti selezionati
    $builder->addEventListener(\Symfony\Component\Form\FormEvents::POST_BIND,
        function($event) {
            $form = $event->getForm();
            $data = $event->getData();

            if(!$data->users->isEmpty()) return;

            $msg = 'Occorre specificare almeno un utente destinatario';
            $form->get('users')->addError(new FormError($msg));
    });
}

Answer 1

Have a look at the validation component: http://symfony.com/doc/current/book/validation.html

You can write a callback constraint within the object you want to validate:

use Symfony\Component\Validator\ExecutionContext;

public function isUsersValid(ExecutionContext $context)
{
    if ($this->users->isEmpty()) {
        $propertyPath = $context->getPropertyPath() . '.users';
        $context->setPropertyPath($propertyPath);
        $context->addViolation('Occorre specificare almeno un utente destinatario', array(), null);
    }
}

See the callback constraint page how to add this constraint to your entity (this depens if you are using annotations or yaml/xml).