Symfony，动态表单修改不会使用匿名函数

Question

好的，这就是问题所在，我在运行php v5.3.27的unix共享主机帐户上使用Symfony 2.3.5。 在我的Symfony项目中，我尝试使用EventListener来动态修改表单，因为我有一些选项在选择客户端之前无法确定。 我一直在按照 Symfony 食谱中的示例来构建表单 http://symfony.com/doc/current/cookbook/form/dynamic_form_modification.html。 我的窗体类中有以下代码：

<?php
// src/Save/ReportBundle/Form/Type/ReportSettingsType.php
namespace SaveReportBundleFormType;
use SymfonyComponentFormAbstractType;
use SymfonyComponentFormFormBuilderInterface;
use SymfonyComponentOptionsResolverOptionsResolverInterface;
use SymfonyComponentFormFormEvent;
use SymfonyComponentFormFormEvents;
class ReportSettingsType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('client', 'entity', array(
                'class'=>'SaveClientBundleEntityClient',
                'property'=>'name',
                'label'=>'Client: ',
                'empty_value' => '-- Select Client --'
            ))
            ->add('newReport', 'choice', array(
                'choices' => array(
                    1 => 'Yes',
                    0 => 'No'
                ),
                'label' => 'Run New Report: ',
                'mapped' => false,
                'expanded' => true,
                'multiple' => false
            ))
            ->add('reportType', 'choice', array(
                'choices' => array(
                    'aggregate' => 'Aggregate',
                    'filtered' => 'Filtered'
                ),
                'label' => 'Report Type: ',
                'expanded' => true,
                'multiple' => false
            ))
            ->add('reportSections', 'choice', array(
                'choices' => array(
                    'welcomeLetter' => 'Welcome Letter Page',
                    'reportDetails' => 'Report Details Page',
                    'qualitativeAnalysis' => 'Qualitative Analysis',
                    'statusSummary' => 'Status Summary Graphs',
                    'existingConditions' => 'Existing Conditions Graphs',
                    'priorityActions' => 'Priority Action Plans',
                    'employeeEngagement' => 'Employee Engagement Benchmarks',
                    'futureDiscussions' => 'Future Discussions'
                ),
                'label' => 'Report Sections: ',
                'multiple' => true,
                'expanded' => true
            ))
            ->add('processReport', 'submit', array(
                'label' => 'Process Report'
            ));                
        $formModifier = function(FormInterface $form, SaveReportBundleEntityReport $report){
            $filters = $data->getClient()->getClientAreas();
            $orders = $data->getClient()->getOrders();
            $form->add('order', 'entity', array(
                'class' => 'SaveOrderBundleEntityOrders',
                'property' => 'selectLabel',
                'choices' => $orders
             ))
             ->add('reportFilter', 'entity', array(
                 'class' => 'SaveClientBundleEntityClientArea',
                 'property' => 'name',
                 'choices' => $filters
             ));
        };
        $builder->addEventListener(
            FormEvents::PRE_SET_DATA,
            function(FormEvent $event){
                $form = $event->getForm();
                $data = $event->getData();
                $formModifier($event->getForm(), $data);
            });
        $builder->get('client')->addEventListener(
            FormEvents::POST_SUBMIT,
            function(FormEvent $event) use ($formModifier){
                $report = $event->getForm()->getData();
                $filters = $report->getClient()->getClientAreas();
                $orders = $report->getClient()->getOrders();
                $formModifier($event->getForm()->getParent(), $report);
            });         
    }
    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'SaveReportBundleEntityReport'
        ));
    }
    public function getParent()
    {
        return 'form';
    }
    public function getName()
    {
        return 'reportsettingstype';
    } 
}
?>

问题出在这条线上$formModifier($event->getForm(), $data);当它调用此线路时，我收到以下消息

FatalErrorException: Error: Function name must be a string in [FILE DIRECTORY]/ReportSettingsType.php line 55

我已经查看了有关匿名函数的PHP文档，这些文档 http://php.net/manual/en/functions.anonymous.php 这些函数利用了PHP闭包类。 根据我到目前为止能够找到的所有内容，这应该按照它的编写方式工作，但我正在尽我的智慧试图弄清楚这一点。

任何建设性的帮助将不胜感激

Answer 1

它缺少闭包的use关键字，以在变量$formModifier中关闭。由于目前在匿名函数中找不到任何名为$formModifier的变量，PHP抱怨。

$builder->addEventListener(
    FormEvents::PRE_SET_DATA,
    function(FormEvent $event){    // use ($formModifier)
        $form = $event->getForm();
        $data = $event->getData();
        $formModifier($event->getForm(), $data);
});