Persistence with Inline Forms

I am trying to customize some inline forms using this guide. I have two models created in my application, "Lesson and Assessment".

Each lesson can have several grades.

I have a form in which the user can create a lesson, as well as as many grades as they want in this lesson. When the form is submitted, it successfully creates the lesson record and all the grade records, however the created grade records are not associated with the parent lesson (the lesson_id field simply remained empty).

Can anyone help?

Any advice is appreciated.

Thank.

My model classes are configured as follows:

Rating:

class Evaluation
{
    /**
     * @var integer
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @ORM\ManyToOne(targetEntity="Lesson", inversedBy="evaluations")
     * @ORM\JoinColumn(name="lesson_id", referencedColumnName="id")
     */
    protected $lesson;

/**
     * Set lesson
     *
     * @param \LessonBundle\Entity\Lesson $lesson
     * @return Evaluation
     */
    public function setLesson(\LessonBundle\Entity\Lesson $lesson = null)
    {
        $this->lesson = $lesson;

        return $this;
    }

    /**
     * Get lesson
     *
     * @return \LessonBundle\Entity\Lesson 
     */
    public function getLesson()
    {
        return $this->lesson;
    }
}

And Lesson:

class Lesson
{
    /**
     * @var integer
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @ORM\OneToMany(targetEntity="Evaluation", mappedBy="lesson", cascade={"persist"})
     */
    protected $evaluations;

    public function __construct()
    {
        $this->evaluations = new ArrayCollection();
    }


    /**
     * Get id
     *
     * @return integer 
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Add evaluations
     *
     * @param \DS\LessonBundle\Entity\Evaluation $evaluations
     * @return Lesson
     */
    public function addEvaluation(\LessonBundle\Entity\Evaluation $evaluations)
    {
        $this->evaluations[] = $evaluations;

        return $this;
    }

    /**
     * Remove evaluations
     *
     * @param \DS\LessonBundle\Entity\Evaluation $evaluations
     */
    public function removeEvaluation(\LessonBundle\Entity\Evaluation $evaluations)
    {
        $this->evaluations->removeElement($evaluations);
    }

    /**
     * Get evaluations
     *
     * @return \Doctrine\Common\Collections\Collection 
     */
    public function getEvaluations()
    {
        return $this->evaluations;
    }

    public function setEvaluations(ArrayCollection $evaluations)
    {
        foreach ($evaluations as $evaluation) {
            $evaluation->setLesson($this);
        }

        $this->evaluations = $evaluations;
    }
}

My controller method:

public function newAction()
{
$lesson = new Lesson;

$evaluation1 = new Evaluation();
$lesson->getEvaluations()->add($evaluation1);
$form    = $this->createForm(new LessonType(), $lesson);
$request = $this->getRequest();

if ($request->getMethod() == 'POST') {
    $form->bindRequest($request);

    if ($form->isValid()) {

        $em = $this->getDoctrine()->getEntityManager();
        $em->persist($lesson);
        $em->flush();

        return $this->redirect($this->generateUrl('lesson_list'));
    }
}

return $this->render('LessonBundle:Lesson:new.html.twig', array('form' => $form->createView()));

}

And my forms are:

class LessonType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('evaluations', 'collection', array(
                                            'type' => new EvaluationType(),
                                            'allow_add' => true,
                                            'by_reference' => false,
                                            ));
    }

    public function getDefaultOptions(array $options)
    {
        return array(
            'data_class' => 'LessonBundle\Entity\Lesson',
        );
    }

    public function getName()
    {
        return 'Lesson';
    }
}

and

class EvaluationType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('report');
    }

    public function getDefaultOptions(array $options)
    {
        return array(
            'data_class' => 'LessonBundle\Entity\Evaluation',
        );
    }

    public function getName()
    {
        return 'Evaluation';
    }
}

And finally, my branch shape template:

{% extends '::base.html.twig' %}

{% block content %}
<form class="vertical" action="" method="post" {{ form_enctype(form) }}>
    {{ form_errors(form) }}

    <ul class="collectionholder" data-prototype="{{ form_widget(form.evaluations.vars.prototype)|e }}">
    {% for evaluation in form.evaluations %}

        <li>{{ form_row(evaluation) }}</li>

    {% endfor %}
    </ul>
    {{ form_rest(form) }}
    <input type="submit" />
</form>
{% endblock %}