Symfony Form EntityType 没有 select 默认情况下呈现的当前值

Question

I stumbled upon an odd behavior and I'm still not sure if my solution is the most appropriate one, even though it works now.

I have 2 entities:

class Recipe
{
    /** [...] */
    public $id;

    /** @ORM\Column(type="string", length=255) */
    public $name;

    /** @ORM\ManyToOne(targetEntity="App\Entity\Location") */
    public $location;
}

class Location
{
    /** [...] */
    public $id;

    /** @ORM\Column(type="string", length=255) */
    public $name;

    /** @ORM\OneToMany(targetEntity="App\Entity\Recipe", mappedBy="location") */
    protected $recipes;
}

Nothing fancy here. A location can hold several recipes, and a recipe can be in one location at most.

The recipe form is built as follows:

    public function buildForm(FormBuilderInterface $builder, array $options) {
        $builder
            ->add(
                'name',
                TextType::class,
                ['label' => 'Name',]
            )
            ->add(
                'location',
                EntityType::class,
                [
                    'label' => 'Location',
                    'class' => \App\Entity\Location::class,
                    'choice_value' => function ($location) {
                        // Why is this code necessary?
                        return is_object($location)
                            ? $location->getId()    // Object passed (when building choices)
                            : $location;            // int value passed (when checking for selection)
                    },
                    'choice_label' => 'name',
                ]
            )
        ;
    }

Then the controller creates the form and so on.

    /**
     * @ParamConverter("entity", class="App:Recipe", isOptional="true")
     */
    public function edit(Request $request, object $entity = null) {
        $form = $this->createForm(\App\Form\Recipe::class, $entity ?? new Recipe());
        $form->handleRequest($request);
        if ($form->isSubmitted() && $form->isValid()) {
            // ...
        }
        // ...
    }

My original implementation didn't have the choice_value callback above on the EntityType form element, and the option was never selected when I opened an existing location. But apart from that, everything was working as expected and selecting a value did save it correctly in the database, without more code but Symfony's magic.

Could you tell me why this choice_value is necessary here? Did I miss something? Why is the value passed as argument is sometimes an object, and sometimes an integer?

Answer 1

I don't know if it is the cause of the problem, but for EntityType field, you don't need to manually set the choice_value .

From Symfony docs :

In the EntityType, this is overridden to use the id by default. When the id is used, Doctrine only queries for the objects for the ids that were actually submitted.

Answer 2

Normally it's not necessary.. Maybe because your relation between entities is uni-directional?

Example that works:

In entity Level

/**
 * @ORM\ManyToOne(targetEntity="App\Entity\Level", inversedBy="steps")
 */
private $level;

In entity Step

/**
 * @ORM\OneToMany(targetEntity="App\Entity\Step", mappedBy="level")
 */
private $steps;

Then StepType:

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        ->add('level', EntityType::class, [
            'label' => 'Related level',
            'class' => Level::class,
            'choice_label' => 'position'
        ])
    ;
}

Answer 3

Oh... Found it. Actually I had an old DataTransformer that was associated to this field and it was messing with the values. I didn't need it anymore anyway so just removing it magically fixed the bug.

Thanks for your help anyway, it did confirm that something wasn't right and forced me to dig deeper.