php - symfony form choice field : set choices option default data from external datasource -

how populate choices option external data array ?

$builder->add('gender', 'choice', array(     'choices' => [array webservice or other class] )); 

documentation show simple static array http://symfony.com/fr/doc/2.7/reference/forms/types/choice.html#choices

i tried :

controller :

$event = new event(); $form = $this->createform(new eventtype($this->get('api')), $event); 

form :

class eventtype extends abstracttype {     protected $myservice;      public function __construct($myservice)     {         $this->myservice = $myservice;     }      public function buildform(formbuilderinterface $builder, array $options)     {         $builder             ->add('titre')             ->add('id_rubrique', 'choice', array(                 'choices' => $this->myservice->getrubriques         ;     }      .... } 

is right solution ?

define form service:

services:     my.form:         class: eventtype         arguments:             - @api 

then in controller:

$event = new event(); $form = $this->createform('my.form', $event);