How to disable specific item in form choice type?

Question

I have a form with choice field of entities from database:

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->add('categories', 'document', array(
        'class' => 'Acme\DemoBundle\Document\Category',
        'property' => 'name',
        'multiple' => true,
        'expanded' => true,
        'empty_value' => false
    ));
}

This form will produce the list of checkboxes and will be rendered as:

[ ] Category 1
[ ] Category 2
[ ] Category 3

I want to disable some of the items by value in this list but I don't know where I should intercept choice field items to do that.

Does anybody know an solution?

Answer 1

Just handled it with finishView and PRE_BIND event listener.

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->add('categories', 'document', array(
        'class' => 'Acme\DemoBundle\Document\Category',
        'property' => 'name',
        'multiple' => true,
        'expanded' => true,
        'empty_value' => false
    ));

    $builder->addEventListener(FormEvents::PRE_BIND, function (FormEvent $event) {
        if (!$ids = $this->getNonEmptyCategoryIds()) {
            return;
        }

        $data = $event->getData();

        if (!isset($data['categories'])) {
            $data['categories'] = $ids;
        } else {
            $data['categories'] = array_unique(array_merge($data['categories'], $ids));
        }

        $event->setData($data);
    });
}

...

public function finishView(FormView $view, FormInterface $form, array $options)
{
    if (!$ids = $this->getNonEmptyCategoryIds()) {
        return;
    }

    foreach ($view->children['categories']->children as $category) {
        if (in_array($category->vars['value'], $ids, true)) {
            $category->vars['attr']['disabled'] = 'disabled';
            $category->vars['checked'] = true;
        }
    }
}