symfony 2 how to pass array collection to input select - php

Question

Hi i am tying pass array collection (method getProjects() returns it) to form (select input) and fail. This code returns exception - A "__toString()" method was not found on the objects of type "Tasker\WebBundle\Entity\Project" passed to the choice field.
Can anybody help? Is needed transformer? Or what is right way?
Controller:
/**
* #Route("/pridaj", name="web.task.add")
* #Template()
*/
public function addAction(Request $request)
{
$task = new Task;
/** #var User $loggedUser */
$loggedUser = $this->get('security.token_storage')->getToken()->getUser();
$form = $this->createForm(new AddTaskType(), $task, ['user' => $loggedUser]);
if ($form->handleRequest($request) && $form->isValid()) {
// some stuff
}
return [
'form' => $form->createView()
];
}
Form:
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('project', 'entity', [
'label' => 'Projekt:',
'class' => 'TaskerWebBundle:Project',
'choices' => $options['user']->getProjects(),
'placeholder' => 'Označte projekt',
])
// ....
}
public function setDefaultOptions(OptionsResolverInterface $resolver)
{
$resolver->setRequired(array(
'user',
));
$resolver->setDefaults(array(
'user' => null,
));
}

Answer 1

just add __ToString() to your Project class
Tasker\WebBundle\Entity\Project
class Project
{
....
function __toString() {
return $this->getName(); //or whatever string you have
}
}

Answer 2

I wanted to add another answer, because you do not have to add __toString() to your Project class. The Symfony entity field type allows you to specify which property/field to use for displaying. So instead of __toString() you could specify the property in the form configuration like so:
$builder
->add('project', 'entity', [
'label' => 'Projekt:',
'class' => 'TaskerWebBundle:Project',
'choices' => $options['user']->getProjects(),
'placeholder' => 'Označte projekt',
'property' => 'name'
])
If you check this part of the Symfony documentation you will see that __toString() is automatically called only if you do not specify the property.