many to many symfony form

Question

I'm trying to set up a multiple choice form with many to many relationship but I keep getting this Error message "Unable to transform value for property path "rozmiar": Expected an array." This is How my Entity looks like:

/**
 * @var ArrayCollection
 * @ORM\ManyToMany(targetEntity="Rozmiar")
 * @ORM\JoinTable(
 *     name="buty__rozmiary",
 *     joinColumns={@ORM\JoinColumn(name="buty_id", referencedColumnName="id")},
 *     inverseJoinColumns={@ORM\JoinColumn(name="rozmiar_id", referencedColumnName="id")}
 * )
 */
private $rozmiar;
 /**
 * Set rozmiar
 *
 * @param ArrayCollection $rozmiar
 * @return rozmiar
 */
public function setRozmiar($rozmiar)
{
    $this->rozmiar = $rozmiar;
    return $this;

}

/**
 * @return ArrayCollection
 */
public function getRozmiar()
{
    return $this->rozmiar;
}

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

And my form:

->add('rozmiar', ChoiceType::class, array(
            'expanded' => true,
            'multiple' => true,
            'choices' => [35,36,37,38,39,40]
            )
        )

What should I do to get this to work? Thanks in advance for your help.

EDIT: I changed the part of my FORM to

->add('rozmiar', EntityType::class, array( 
'class' => 'ShoeShopBundle:Buty',
'expanded' => true,
'multiple' => true,
'choices' => [35,36,37,38,39,40] ))

and now I'm getting "Warning: spl_object_hash() expects parameter 1 to be object, integer given" error. What is the proper way to define choices in this kind of field?

Answer 1

You need an EntityType field

->add('rozmiar', EntityType::class, array(
    'class' => 'MyBundle:Rozmiar',
    'multiple' => true,
    'expanded' => true,
    'choices' => $editedObject->getRozmiarChoices(),
))

with

$editedObject = $builder->getData();

be carefull to edit addRozmiar Method for the added rozmiar to know that new link :

public function addRozmiar(\MyBundle\Entity\Rozmiar $rozmiar)
{
    if (!$this->rozmiar->contains($rozmiar)) {
        $this->rozmiar->add($rozmiar);
        $rozmiar->addButy($this);
    }
    return $this;
}

in Symfony2 I also often needed to add this value in the form, in order to force your method usage : 'by_reference' => false,

more infos : http://symfony.com/doc/current/reference/forms/types/entity.html

---

Edit :

Your choice list need to be an array or an arrayCollection of objects of class "MyBundle:Rozmiar". not integers. You can also use the 'query_builder' option instead of the 'choices' one if the list is not specificly related to your edited object.

see here : http://symfony.com/doc/current/reference/forms/types/entity.html#using-a-custom-query-for-the-entities

Your list [35,36,37,38,39,40] shouldn't be hard coded in your form. You should put it in your entity if this is an enum, or add a boolean field in your other table in ordrer to use the query builder to find them.

I hope this will help :)