symfony : can't we have a hidden entity field?

Question

I am rendering a form with an entity field in symfony.

It works well when i choose a regular entity field.

$builder
    ->add(\'parent\',\'entity\         


        

Answer 1

With Symfony 5, I use the solution of a Hidden type that implements DataTransformerInterface interface.

dm = $doctrine;
    }

    /**
     *
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options): void
    {
        // Set class, eg: App\Entity\RuleSet
        $this->entityClass = sprintf('App\Entity\%s', ucfirst($builder->getName()));
        $builder->addModelTransformer($this);
    }

    public function transform($data): string
    {
        // Modified from comments to use instanceof so that base classes or interfaces can be specified
        if (null === $data || !$data instanceof $this->entityClass) {
            return '';
        }

        $res = $data->getId();

        return $res;
    }

    public function reverseTransform($data)
    {
        if (!$data) {
            return null;
        }

        $res = null;
        try {
            $rep = $this->dm->getRepository($this->entityClass);
            $res = $rep->findOneBy(array(
                "id" => $data
            ));
        }
        catch (\Exception $e) {
            throw new TransformationFailedException($e->getMessage());
        }

        if ($res === null) {
            throw new TransformationFailedException(sprintf('A %s with id "%s" does not exist!', $this->entityClass, $data));
        }

        return $res;
    }
}

And to use the field in the form:

use App\Form\Type\EntityHiddenType;

public function buildForm(FormBuilderInterface $builder, array $options): void
{
    // Field name must match entity class, eg 'ruleSet' for App\Entity\RuleSet
    $builder->add('ruleSet', EntityHiddenType::class);
}