Symfony 3:将$options参数值从formType发送到underFormType

use Symfony\Component\OptionsResolver\OptionsResolver;

public function configureOptions(OptionsResolver $resolver)
{
    $resolver->setDefaults([
        'options' => null,
    ]);
}

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class MyFormType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            // 添加其他字段
            ->add('underForm', UnderFormType::class, [
                'options' => $options['options'],
            ]);
    }

    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults([
            'options' => null,
        ]);
    }
}

$form = $this->createForm(MyFormType::class, null, [
    'options' => 'some value',
]);