Sulu custom dropdown content ty-e

Dropdown.php

<?php

namespace AppBundle\Sulu\Content\Type;

use Sulu\Component\Content\Compat\PropertyInterface;
use Sulu\Component\Content\Compat\PropertyParameter;
use Sulu\Component\Content\SimpleContentType;

/**
 * ContentType for a dropdown and selecting one option.
 * Based on Sulu's own SingleSelect
 */
class Dropdown extends SimpleContentType
{
    /**
     * @var string
     */
    private $template;

    public function __construct($template)
    {
        parent::__construct('Dropdown', '');
        $this->template = $template;
    }

    /**
     * {@inheritdoc}
     */
    public function getTemplate()
    {
        return $this->template;
    }

    /**
     * {@inheritdoc}
     */
    public function getDefaultParams(PropertyInterface $property = null)
    {
        return [
            'values' => new PropertyParameter('values', [], 'collection'),
        ];
    }
}


Template File:

<select name="{{ id|raw }}"
        class="preview-update trigger-save-button form-element"
        data-property='{{ property|json_encode }}'
        data-mapper-property="{{ property.name }}">
{% for value in params.values.value %}
    {% set elementId %}{{ id|raw }}_{{ loop.index }}{% endset %}
    <option name="{{ id|raw }}"
            value="{{ value.name }}">
        {{ value.getTitle(userLocale) }}
    </option>
{% endfor %}
</select>

Add to services:

<service id="app.sulu.content.type.dropdown" class="%app.sulu.content.type.dropdown.class%">
    <argument>@AppBundle/Sulu/Content/Type/dropdown.html.twig</argument>
    <tag name="sulu.content.type" alias="dropdown"/>
</service>