How to change the appearance of an EntityType in Symfony2?

Question

symfony

There is a field parent, EntityType

$builder->add('parent', EntityType::class, array(
                'class' => 'AdBundle:AdLocation',
                'choice_label' => 'title',
                'query_builder' => function(EntityRepository $er) {
                    return $er->createQueryBuilder('l')
                        ->where('l.visible = :visible')
                        ->setParameter('visible', true);
                }
            ))

The field is represented as a list of location categories: Country, City, District.
I want to change the output in the dropdown list in the format:
- Country
- - City
- - - District
How can I do this?

Answer 1

In general, if your countries, cities and districts are stored in different tables, you can use dependent fields. For example, one of their such implementations is ShtumiUsefulBundle .
It can be expensive to display everything in one field at once, and the client’s page can slow down.