Symfony2，如何在樹枝文件中投射數據類型？

Question

我有一些場景象下面這樣：

/** 
* @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，我想，讓他們：

{{ role.rolesFeatures.getId() }} 

我得到這個：

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. 

我如何可以投學說\ ORM \ PersistentCollection它真正的對象類？

Answer 1

rolesFeatures是一個數組，因此您需要遍歷它。喜歡的東西：

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