php - Symfony2 : Change choices with ajax and validation

场景:我有一个带有2个选择的表格。当用户从第一个选择中选择某项时，第二个选择将填充新值。这部分工作正常。

但是该表单未得到验证，因为它包含初始表单中不允许的某些选项。

形式:

<?php

class MyType extends AbstractType
{
    private $category;

    public function __construct($category = null)
    {
        $this->category = $category;
    }

    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('category', 'choice', array(
            'choices' => array(
                'foo' => 'foo',
                'bar' => 'bar'
            )
        );

        $builder->add('template', 'choice', array(
            'choices' => $this->loadChoices()
        );
    }

    private function loadChoices()
    {
        // load them from DB depending on the $this->category
    }
}

最初，类别为foo。因此，将foo的模板加载并设置为选项。但是，如果用户选择bar，则将加载条形模板。但是该表格仍然具有foo选项，并且无法验证。

解决此问题的最佳方法是什么？

我发现的一种方法是仅在 Controller 中重新初始化表单:

<?php

$form = $this->createForm(new MyType());

if ($request->getMethod() === 'POST') {
    if ($request->request->has($form->getName())
        && isset($request->request->get($form->getName())['category'])) {
            $form = $this->createForm(new MyType($request->request->get($form->getName())['category']));
    }

    // ...
}

这行得通，但是我无法测试它，因为在设置该值时会抛出IllegalArgumentException，并且仅假设默认值。有什么更好的解决方案吗？提前致谢!

最佳答案

我认为您必须使用事件来管理此问题，这是更正确的方法

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->add('category', 'choice', array(
        'choices' => array(
            'foo' => 'foo',
            'bar' => 'bar'
        )
    ));

    $ff = $builder->getFormFactory();

    // function to add 'template' choice field dynamically
    $func = function (FormEvent $e) use ($ff) {
        $data = $e->getData();
        $form = $e->getForm();
        if ($form->has('template')) {
            $form->remove('template');
        }

        $cat = isset($data['category'])?$data['category']:null;

        // here u can populate ur choices in a manner u do it in loadChoices
        $choices = array('1' => '1', '2' => '2');
        if ($cat == 'bar') {
            $choices = array('3' => '3', '4' => '4');
        }

        $form->add($ff->createNamed('template', 'choice', null, compact('choices')));
    };

    // Register the function above as EventListener on PreSet and PreBind
    $builder->addEventListener(FormEvents::PRE_SET_DATA, $func);
    $builder->addEventListener(FormEvents::PRE_BIND, $func);
}