php - 无法从表单类型的查询构建器函数访问全局变量

Question

我正在尝试将参数设置为表单类型的查询生成器。我想设置 impact 变量以形成字段查询生成器。我从表单选项中获得影响

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->add('title');

    $parentPage = $options["parentPage"];
    $impact = $options["impact"];

    if($parentPage != null){
        $builder->add('parent', 'entity', array(
            'class' => "CoreBundle:Page",
            'choices' => array($parentPage)
        ));
    }else{
        $builder->add('parent', 'entity', array(
            'class' => "CoreBundle:Page",
            'query_builder' => function(PageRepository $pr){
                $qb = $pr->createQueryBuilder('p');
                $qb->where("p.fullPath NOT LIKE '/deleted%'");

                $qb->andWhere('p.impact = :impact')
                    ->setParameter('impact', $impact); <-'Undefined variable $impact'

                return $qb;
            },
        ));
    }

为什么这段代码显示是错误的，它说 $impact 是 undefined variable 。不是可以在buildForm函数的任何地方访问的全局变量吗？

Answer 1

问题是您需要显式指定传递给闭包的变量(也称为 query_builder 函数):

    $builder->add('parent', 'entity', array(
        'class' => "CoreBundle:Page",
        'query_builder' => function(PageRepository $pr) use ($impact) { // ADD
            $qb = $pr->createQueryBuilder('p');
            $qb->where("p.fullPath NOT LIKE '/deleted%'");

            $qb->andWhere('p.impact = :impact')
                ->setParameter('impact', $impact); <-'Undefined variable $impact'

            return $qb;
        },
    ));

大多数语言不需要这个，但 php 需要。 参见示例 3:http://php.net/manual/en/functions.anonymous.php