Data lists: Create a custom field type

When none of the built-in field types fit your needs, you can create your own by extending AbstractFieldType.

Create the field type

namespace App\Datalist\Field\Type;

use Leapt\CoreBundle\Datalist\Field\DatalistFieldInterface;
use Leapt\CoreBundle\Datalist\Field\Type\AbstractFieldType;
use Leapt\CoreBundle\Datalist\ViewContext;
use Symfony\Component\OptionsResolver\OptionsResolver;

class RatingFieldType extends AbstractFieldType
{
    public function configureOptions(OptionsResolver $resolver): void
    {
        parent::configureOptions($resolver);

        $resolver->setDefaults([
            'max' => 5,
        ]);
        $resolver->setAllowedTypes('max', 'int');
    }

    public function buildViewContext(ViewContext $viewContext, DatalistFieldInterface $field, mixed $value, array $options): void
    {
        parent::buildViewContext($viewContext, $field, $value, $options);

        $viewContext['max'] = $options['max'];
    }

    public function getName(): string
    {
        return 'rating';
    }

    public function getBlockName(): string
    {
        return 'rating';
    }
}

• configureOptions() declares the options your field type accepts, on top of the common field options it already inherits from AbstractFieldType. It follows the same OptionsResolver API used by Symfony forms.
• buildViewContext() populates the variables made available to the Twig block. Always call parent::buildViewContext() first: it resolves value (through property_path or callback), and exposes field, options and translation_domain. Note that the $value argument it receives is the current row, not the field's own resolved value — that's why parent::buildViewContext() needs it to compute value via property_path.
• getBlockName() is used to resolve which Twig block renders the field (see below).
• getName() is required by the interface but isn't used to render fields; it just needs to return a unique string.

You don't need to register the field type anywhere: any service implementing FieldTypeInterface is automatically tagged and picked up by the bundle, as long as your app has autoconfigure: true (the Symfony default).

Render it in a Datalist theme

The block rendered for a field is named after getBlockName(), suffixed with _field — here, rating_field. Add it to your own Datalist theme (see Render the Data list):

{% extends '@LeaptCore/Datalist/datalist_grid_layout.html.twig' %}

{% block rating_field %}
    <td>
        {% if value is not null %}
            {% for i in 1..value %}⭐{% endfor %} <span class="text-muted">/ {{ max }}</span>
        {% else %}
            <span class="empty-value">{{ 'datalist.empty_value'|trans({}, 'LeaptCoreBundle') }}</span>
        {% endif %}
    </td>
{% endblock rating_field %}

All the variables set on $viewContext in buildViewContext() (value, options, max, ...) are available in the block.

Overriding a single field instance

If you need a different rendering for one specific field of one specific Datalist type, you can instead define a block named _<datalist type's block name>_<field name>_field — e.g. _datalist_rating_field for a field named rating on a Datalist type whose getBlockName() returns the default datalist — which takes precedence over rating_field for that field only.

Use it

$builder
    ->addField('rating', RatingFieldType::class, [
        'max' => 10,
    ])
    ->getDatalist();

Go back to Data lists documentation