Load choices into form choice field from entity method

Question

I have symfony form with choice field. I want to load choices from my entity class static method. can i use data or CallbackChoiceLoader? what is the best practise?

this is my field:

        class CarType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        ->add('type', ChoiceType::class, [
            // This choices I would like to load from:
            // 'choices' => $car::getTypes(),
            'choices'       => [
                'Critical'  => 'critical',
                'Medium'    => 'medium',
                'Info'      => 'info',
            ],
            'label'         => 'Type'
        ])
        ->add('name', TextType::class, [
            'label' => 'Name'
        ])
        ->add('save', SubmitType::class, [
            'label' => 'Save'
        ])
    ;
}

public function configureOptions(OptionsResolver $resolver)
{
    $resolver->setDefaults([
        'data_class' => 'AppBundle\Entity\Car'
    ]);
}

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

This is my entity:

/**
 * @ORM\Entity
 * @ORM\Table(name="car")
 */
class Car
{
/**
 * @var integer
 *
 * @ORM\Column(name="id", type="integer", nullable=false)
 * @ORM\Id
 * @ORM\GeneratedValue(strategy="IDENTITY")
 */
private $id;

/**
 * @var string $type
 *
 * @Assert\NotBlank()
 * @ORM\Column(name="type")
 */
private $type;

/**
 * @var string $name
 *
 * @Assert\NotBlank()
 * @ORM\Column(name="name")
 */
private $name;

/**
 * @var \DateTime $created
 *
 * @ORM\Column(name="created", type="datetime")
 */
private $created;

private static $types = ['main', 'custom'];

public function __construct()
{
    $this->created = new \DateTime('now', new \DateTimeZone('Europe/Ljubljana'));
}

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

/**
 * Get types
 * 
 * @return array
 */
public function getTypes()
{
    return self::$types;
}

/**
 * Set type
 *
 * @param string $type
 *
 * @return Car
 */
public function setType($type)
{
    if (in_array($type, $this->getTypes())) {
        $this->type = $type;
    }

    return $this;
}

/**
 * Get type
 *
 * @return string
 */
public function getType()
{
    return $this->type;
}

/**
 * Set name
 *
 * @param string $name
 *
 * @return Car
 */
public function setName($name)
{
    $this->name = $name;

    return $this;
}

/**
 * Get name
 *
 * @return string
 */
public function getName()
{
    return $this->name;
}

/**
 * Set created
 *
 * @param \DateTime $created
 *
 * @return Car
 */
public function setCreated($created)
{
    $this->created = $created;

    return $this;
}

/**
 * Get created
 *
 * @return \DateTime
 */
public function getCreated()
{
    return $this->created;
}

How and what can i use to load choices from $car::getTypes() method like i commented in form so that the choices are loaded dynamicly based on values in getTypes entity method?

Answer 1

Edit: This is option 1. Option 2 below more directly answers the question.

The preferred method of creating a choice form field from an entity is to use the EntityType field. Here is an example from an application that requires an ethnicity field. Below that is the Ethnicity entity.

form field:

->add('ethnicity', EntityType::class, array(
    'label' => 'Ethnicity:',
    'class' => 'AppBundle:Ethnicity',
    'choice_label' => 'abbreviation',
    'expanded' => false,
    'placeholder' => 'Select ethnicity',
    'query_builder' => function (EntityRepository $er) {
        return $er->createQueryBuilder('e')
                ->orderBy('e.abbreviation', 'ASC')
        ;
    },
))

Ethnicity entity:

/**
 * Ethnicity.
 *
 * @ORM\Table(name="ethnicity")
 * @ORM\Entity
 */
class Ethnicity
{
    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="IDENTITY")
     */
    protected $id;

    /**
     * @var string
     *
     * @ORM\Column(name="ethnicity", type="string", length=45, nullable=true)
     */
    protected $ethnicity;

    /**
     * @var string
     *
     * @ORM\Column(name="abbr", type="string", length=45, nullable=true)
     */
    protected $abbreviation;

    /**
     * @var \Doctrine\Common\Collections\Collection
     *
     * @ORM\OneToMany(targetEntity="AppBundle\Entity\Member", mappedBy="ethnicity", cascade={"persist"})
     */
    protected $members;

    /**
     * Constructor.
     */
    public function __construct()
    {
        $this->members = new \Doctrine\Common\Collections\ArrayCollection();
    }

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

    /**
     * Set ethnicity.
     *
     * @param string $ethnicity
     *
     * @return Ethnicity
     */
    public function setEthnicity($ethnicity)
    {
        $this->ethnicity = $ethnicity;

        return $this;
    }

    /**
     * Get ethnicity.
     *
     * @return string
     */
    public function getEthnicity()
    {
        return $this->ethnicity;
    }

    /**
     * Set abbreviation.
     *
     * @param string $abbreviation
     *
     * @return Ethnicity
     */
    public function setAbbreviation($abbreviation)
    {
        $this->abbreviation = $abbreviation;

        return $this;
    }

    /**
     * Get abbreviation.
     *
     * @return string
     */
    public function getAbbreviation()
    {
        return $this->abbreviation;
    }

    /**
     * Add members.
     *
     * @param \AppBundle\Entity\Member $members
     *
     * @return Ethnicity
     */
    public function addMember(\AppBundle\Entity\Member $members)
    {
        $this->members[] = $members;

        return $this;
    }

    /**
     * Remove members.
     *
     * @param \AppBundle\Entity\Member $members
     */
    public function removeMember(\Truckee\ProjectmanaBundle\Entity\Member $members)
    {
        $this->members->removeElement($members);
    }

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

    /**
     * @var bool
     *
     * @ORM\Column(name="enabled", type="boolean", nullable=true)
     */
    protected $enabled;

    /**
     * Set enabled.
     *
     * @param bool $enabled
     *
     * @return enabled
     */
    public function setEnabled($enabled)
    {
        $this->enabled = $enabled;

        return $this;
    }

    /**
     * Get enabled.
     *
     * @return bool
     */
    public function getEnabled()
    {
        return $this->enabled;
    }
}

Option 2: If you really want to do that, then here's an approach:

1. Modify your static property $types such that the choices are values in an array, e.g., $types = array(1 => 'main', 2 => 'custom')
2. In your controller, add a use statement for the Car entity.

3. In controller action:

   $car = new Car();

   $types = $car->getTypes;

4. Use the answer to Passing data to buildForm() in Symfony 2.8/3.0 to see how to pass $types to your form.