在Symfony2中预先选择具有就绪实体的表单

想要在Symfony中预先选择我的表格。我使用“表单”构建器完成此操作。它起作用，除了子表未保存。

我的发票类型

    public function buildForm(FormBuilderInterface $builder, array $options) {

    $builder
            ->add('invoiceNumber', 'hidden', array('label' => ''))
            ->add('date', 'date', array('label' => 'Field', 'data' => new \DateTime("now")))
            ->add('PaidPrice', 'money', array('label' => 'Bereits bezahlt', 'attr' => array('class' => '')))
            ->add('invoicepos', 'collection', array(
                    'type' => new InvoiceposType(),
                    'allow_add'    => true,
                    'allow_delete' => true,
                    'cascade_validation' => true,
                    'by_reference' => true,
                ))
    ;
}

我的发票类型

    public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        ->add('pos', 'text', array('label' => '', 'attr' => array()))
        ->add('quantity', 'hidden')
        ->add('price', 'hidden')
        ->add('tax', 'hidden')
    ;
}

我的控制器启动表格

public function newAction($id) {
    $em->persist($entInvoice);
    //$em->flush($entInvoice); //works perfect, but i dont want to save that, just pre select for the form
    $form = $this->createCreateForm($entInvoice);
    return array(
        'entity' => $entInvoice,
        'form' => $form->createView(),
    );
}

我提交表格时的代码

public function createAction(Request $request) {
    $entity = new Invoice();
    $form = $this->createCreateForm($entity);
    $form->handleRequest($request);

    if ($form->isValid()) {
        $em = $this->getDoctrine()->getManager();
        $em->persist($entity);
        $em->flush();

        return $this->redirect($this->generateUrl('pspiess_letsplay_invoice_show', array('id' => $entity->getId())));
    }

    return array(
        'entity' => $entity,
        'form' => $form->createView(),
    );
}

数据在那里，但是没有关系！

我怎么了 感谢帮助。