Pass one id to a composite key in form - symfony

Question

I have a form in which I chose student id and a id of a course which make a composite key in a UserCourse entity, and with that a status of that course (passed, enrolled etc).
What I want is to pass the value of currently logged in student to the form to populate the userid field with current user id, so that it only has to choose the course and status and submit it.
I have tried using default_value and data => $userId but failed.
This is the UserController
/**
* #Route("/courses/{userId}/new", name="new_usercourse")
*/
public function newMylistAction(Request $request, $userId)
{
$userCourse = new UserCourse();
$userCourse->setUserId($userId);
$form = $this->createForm('AppBundle\Form\UserCourseType', $userCourse);
$form->handleRequest($request);
if ($form->isSubmitted() && $form->isValid()) {
$em = $this->getDoctrine()->getManager();
$em->persist($userCourse);
$em->flush();
return $this->redirectToRoute('mycourses');
}
return $this->render('student/new_mycourses.html.twig', array(
'usercourse' => $userCourse,
'form' => $form->createView()
));
}
This is the UserCourseType Form. userId is also an EntityType
namespace AppBundle\Form;
use AppBundle\Entity\Course;
use AppBundle\Entity\UserCourse;
use Symfony\Bridge\Doctrine\Form\Type\EntityType;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;
class UserCourseType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('userId', null)
->add('courseId', EntityType::class, array(
'class' => 'AppBundle\Entity\Course',
'choice_label' => 'name'
))
->add('status', ChoiceType::class, array(
'choices' => array(
'Passed' => 'passed',
'Enrolled' => 'enrolled',
'Null' => '',
)))
->add('save', SubmitType::class, array('label' => 'Create'));
}
public function configureOptions(OptionsResolver $resolver)
{
$resolver->setDefaults(array(
'data_class' => UserCourse::class
));
}
}
Hope you can help

Answer 1

before flush() set user id
if ($form->isSubmitted() && $form->isValid()) {
$em = $this->getDoctrine()->getManager();
$userCourseRepo=$em->getRepository('AppBundle:UserCourse');
$userCourseIddata = $userCourseRepo->find($id);
$userCourse->setUserId($userCourseIddata);////set userid
$em->persist($userCourse);
$em->flush();
return $this->redirectToRoute('mycourses');
}