php – 如何在symfony 2表单生成器中向选项元素添加自定义属性

以下面的形式为例：

class FooForm extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder,array $options)
    {
        $builder->add('user','choice',array(
            'choices' => array(
                 'designers'=>'designers','1'=>'mike','2'=>'carroll','developers'=>'developers','3'=>'chase','4'=>'brett','5'=>'jordan',)
        ));
    }
}

然后在渲染时我需要它看起来像：

<select>
    <option value="" disabled="disabled">designers</option>
    <option value="1">mike</option>
    <option value="2">carroll</option>
    <option value="" disabled="disabled">developers</option>
    <option value="3">chase</option>
    <option value="4">brett</option>
    <option value="5">jordan</option>
</select>

我所期待的将是这样的：

class FooForm extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder,array(
            'choices' => array(
                 'designers'=>array(
                      'label'=>'designers','attr'=>arrry('disabled'=>'disabled')
                 ),'developers'=>array(
                      'label'=>'developers',)
        ));
    }
}

但那不起作用.所以对此的任何帮助将不胜感激.