如何在Symfony2中为表单集合正确设置'data_class'？

Question

I would like to have a collection of forms. My brick form is defined like:

class ImportPaymentsType extends AbstractType
{
    public function getName()
    {
        return 'import_payments_type';
    }

    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('caisse', 'entity', array(
            'label' => null,
            'class' => 'ACME\AppBundle\Entity\Caisse',
            'property' => 'name',
            'empty_value' => 'Choose an option',
        ))
        ->add('label', 'text', array(
            'label' => null,
        ))
        ->add('credit', 'number', array(
            'label' => null,
        ));
    }
}

In controller I construct this form like:

    $data = array(
        'imports' =>
            array(
                'caisse' => $em->getRepository('ACMEAppBundle:Caisse')->findOneByCode('P6015C'),
                'label' => null,
                'credit' => null,
            )
    );

    $importForm = $this->createFormBuilder($data)
        ->add('imports', 'collection', array(
            'type' => new ImportPaymentsType(),
        ))->getForm();

The error I get is:

The form's view data is expected to be of type scalar, array or an instance of \ArrayAccess, but is an instance of class ACME\AppBundle\Entity\Caisse. You can avoid this error by setting the "data_class" option to "ACME\AppBundleBundle\Entity\Caisse" or by adding a view transformer that transforms an instance of class ACME\AppBundleBundle\Entity\Caisse to scalar, array or an instance of \ArrayAccess.

I tried to change ImportPaymentsType but it didn't work:

    ->add('caisse', 'entity', array(
        'label' => null,
        'class' => 'ACME\AppBundle\Entity\Caisse',
        'property' => 'description',
        'empty_value' => 'Choose an option',

        'data_class' => 'ACME\AppBundle\Entity\Caisse'

    ))

What should I do? Please help.

Answer 1

'imports' should be an array of array.

Try with:

$data = array(
    'imports' =>
        array(
            array(
                'caisse' => $em->getRepository('ACMEAppBundle:Caisse')->findOneByCode('P6015C'),
                'label' => null,
                'credit' => null,
            )
        )
);