Symfony2，如何在树枝文件中转换数据类型？

Question

我有一些类似下面的场景：

/**
 * @ORM\Entity
 * @ORM\Table(name="role")
 */
class Role
{
    /**
     * @ORM\OneToMany(targetEntity="RolesFeatures", mappedBy="role", cascade={"all"})
     **/
    private $rolesFeatures;
}

在我的索引文件中我想得到它们：

{{ role.rolesFeatures.getId() }}

我明白了：

 An exception has been thrown during the rendering of a template ("Catchable Fatal
 Error: Object of class Doctrine\ORM\PersistentCollection could not be converted to string
 in C:\wamp\www\PMI_sf2\app\cache\dev\twig\63\81\679fca1c2da64d0ebbcd5661bc6d.php line 99")
 in PMIHomePagesBundle:HomePages:mainHome.html.twig at line 49.

如何将 Doctrine\ORM\PersistentCollection 转换为真实的对象类？

Answer 1

rolesFeatures 是一个数组，因此您需要对其进行迭代。比如：

{% for roleFeature in role.rolesFeatures %}
    {{ roleFeature.id }}
{% endfor %}