symfony2 - adding choices from database

Question

I am looking to populate a choice box in symfony2 with values from a custom query. I have tried to simplify as much as possible.

Controller

class PageController extends Controller
{

    public function indexAction()
    {
      $fields = $this->get('fields');
      $countries =  $fields->getCountries(); // returns a array of countries e.g. array('UK', 'France', 'etc')
      $routeSetup = new RouteSetup(); // this is the entity
      $routeSetup->setCountries($countries); // sets the array of countries

      $chooseRouteForm = $this->createForm(new ChooseRouteForm(), $routeSetup);


      return $this->render('ExampleBundle:Page:index.html.twig', array(
        'form' => $chooseRouteForm->createView()
      ));

    }
}

ChooseRouteForm

class ChooseRouteForm extends AbstractType
{

  public function buildForm(FormBuilderInterface $builder, array $options)
  {

    // errors... ideally I want this to fetch the items from the $routeSetup object 
    $builder->add('countries', 'choice', array(
      'choices' => $this->routeSetup->getCountries()
    ));

  }

  public function getName()
  {
    return 'choose_route';
  }
}

Answer 1

You could pass the choices to your form using..

$chooseRouteForm = $this->createForm(new ChooseRouteForm($routeSetup), $routeSetup);

Then in your form..

private $countries;

public function __construct(RouteSetup $routeSetup)
{
    $this->countries = $routeSetup->getCountries();
}

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->add('countries', 'choice', array(
        'choices' => $this->countries,
    ));
}

Updated (and improved) for 2.8+

Firstly you don't really need to pass in the countries as part of the route object unless they are going to be stored in the DB.

If storing the available countries in the DB then you can use an event listener. If not (or if you don't want to use a listener) you can add the countries in the options area.

Using Options

In the controller..

$chooseRouteForm = $this->createForm(
    ChooseRouteForm::class,
    // Or the full class name if using < php 5.5
    $routeSetup,
    array('countries' => $fields->getCountries())
);

And in your form..

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->add('countries', 'choice', array(
        'choices' => $options['countries'],
    ));
}

public function configureOptions(OptionsResolver $resolver)
{
    $resolver
        ->setDefault('countries', null)
        ->setRequired('countries')
        ->setAllowedTypes('countries', array('array'))
    ;
}

Using A Listener (If the countries array is available in the model)

In the controller..

$chooseRouteForm = $this->createForm(
    ChooseRouteForm::class,
    // Or the full class name if using < php 5.5
    $routeSetup
);

And in your form..

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        ->addEventListener(FormEvents::PRE_SET_DATA, function(FormEvent $event) {
            $form = $event->getForm();
            /** @var RouteSetup $routeSetup */
            $routeSetup = $event->getData();

            if (null === $routeSetup) {
                throw new \Exception('RouteSetup must be injected into form');
            }

            $form
                ->add('countries', 'choice', array(
                    'choices' => $routeSetup->getCountries(),
                ))
            ;
        })
    ;
}

Answer 2

I can't comment or downvote yet, so I'll just reply to Qoop's answer here: What you proposed will work unless you start using your form type class as a service. You should generally avoid adding data to your form type object through constructor.

Think of form type class like a Class - it's a kind of description of your form. When you make an instance of form (by building it) you get the Object of form that is build by the description in form type and then filled with data.

Take a look at this: http://www.youtube.com/watch?v=JAX13g5orwo - this situation is described around 31 minute of the presentaion.

You should use form event FormEvents::PRE_SET_DATA and manipulate fields when the form is injected with data. See: http://symfony.com/doc/current/cookbook/form/dynamic_form_modification.html#customizing-your-form-based-on-the-underlying-data