Symfony2: How call the repository of an entity in the FormType

Question

I tried to call the repository of my entity Category in the class form of my entity BonCommande, but this error ocuured:

Notice:

Answer 1

FormComponent is an independent component and it doesn't provide any entityManager to use. You have to inject it or pass it by $options if you want to use it..

In your case it would be correct if you directly pass it to the type's __construct or pass by $options array or declare your type as a service and inject entity manager to it:

class BonCommandeType extends AbstractType
{
    private $em;

    public function __construct(EntityManagerInterface $em)
    {
        $this->em = $em;
    }

    ...
}

or

$this->createForm(TYPE, DATA, ['em' => $em]);

Answer 2

From your code I assume you are missing this:

//Somewhere at the begging of your BonCommandeType
protected $em;
...
public function __construct(EntityManager $em) 
{
    $this->em = $em;
}

Keep in mind that when you create a new form object you should use smth like :

BonCommandeType($this->getDoctrine()->getManager()) // if inside a controller