| | - `choice_filter`_ |

.. include:: /reference/forms/types/options/choice_filter.rst.inc

``choice_filter``

~~~~~~~~~~~~~~~~~

**type**: ``callable``, ``string`` or :class:`Symfony\\Component\\PropertyAccess\\PropertyPath` **default**: ``null``

.. versionadded:: 5.1

The ``choice_filter`` option has been introduced in Symfony 5.1.

When using predefined choice types from Symfony core or vendor libraries (i.e.

:doc:`CountryType </reference/forms/types/country>`) this option lets you

define a callable that take each choice as only argument and must return

``true`` to keep it or ``false`` to discard it::

// src/Form/Type/AddressType.php

namespace App\Form\Type;

use Symfony\Component\Form\AbstractType;

use Symfony\Component\Form\Extension\Core\Type\CountryType;

use Symfony\Component\Form\FormBuilderInterface;

use Symfony\Component\OptionsResolver\OptionsResolver;

class AddressType extends AbstractType

{

public function configureOptions(OptionsResolver $resolver)

{

$resolver

->setDefaults([

// enable this type to accept a limited set of countries

'allowed_countries' => null,

])

;

}

public function buildForm(FormBuilderInterface $builder, array $options)

{

$allowedCountries = $options['allowed_countries'];

$builder

// ...

->add('country', CountryType::class, [

// if the AddressType "allowed_countries" option is passed,

// use it to create a filter

'choice_filter' => $allowedCountries ? function ($countryCode) use ($allowedCountries) {

return in_array($countryCode, $allowedCountries, true);

} : null,

])

;

}

The option can be a callable or a property path when choices are objects::

// ...

$builder

->add('category', ChoiceType::class, [

// ...

'choice_filter' => 'isSelectable',

])

;

.. tip::

Considering this ``AddressType`` could be an entry of a ``CollectionType``

you should use the :class:`Symfony\\Component\\Form\\ChoiceList\\ChoiceList`

class helper to enable caching::

// src/Form/Type/AddressType.php

// ...

use Symfony\Component\Form\ChoiceList\ChoiceList;

// ...

'choice_filter' => $allowedCountries ? ChoiceList::filter(

// pass the type as first argument

$this,

function ($countryCode) use ($allowedCountries) {

return in_array($countryCode, $allowedCountries, true);

},

// pass the option that makes the filter "vary" to compute a unique hash

$allowedCountries

) : null,

// ...