[Symfony] Injecting object to form type to generate related data only

symfony-form-object-inject.php

<?php
/**
*  This example is to inject object into the form type in order to generate entity field with related data only. Rather than loading the whole entity
*  So if we have Order and we want to list its order lines.
*
*  To call this code from Contoller
*
*        $order = $this->getDoctrine()->getRepository('OrderBundle:Order')->find(100);
*        $form =  $this->createForm(new ReturnOrderType($order), $order);
*/
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
use Oras\OrderBundle\Entity\Order;

/**
 * This class will generate the form builder for rules
 */
class ReturnOrderType extends AbstractType
{
    
    protected $order;
    public function __construct(Order $order)
    {
      $this->order = $order;    
    }
    /**
     * @param FormBuilderInterface $builder
     * @param array                $options
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $order = $this->order;
        $builder
                ->add('orderLines', 'entity', array(
                    'class'    => 'Worldstores\OrderBundle\Entity\OrderLine',
                    'property' => 'id',
                    'multiple' => true,
                    'expanded' => true,
                    'query_builder' => function(\Doctrine\ORM\EntityRepository $er) use ($order) {
                        $qb = $er->createQueryBuilder('ol')
                        ->leftJoin('ol.order', 'o')
                        ->where('o = :order')
                        ->setParameter(':order',$order);
                        return $qb;
                    }
                );
        );
    }

    /**
     * @param OptionsResolverInterface $resolver
     */
    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'Oras\OrderBundle\Entity\Order'
        ));
    }

    /**
     * @return string
     */
    public function getName()
    {
        return 'oras_orderbundle_orderlines';
    }
}