Symfony2CookBook：如何使用虛拟的表單域選項

The virtual form field option can be very useful when you have some duplicated fields in different entities.

當您在不同的實體中擁有一些重複的表單域時，虛拟表單域選項就顯得非常有用。

For example, imagine you have two entities, a Company and a Customer:

舉個例子，想象您有兩個實體，Company和Customer：

Company實體：

// src/Acme/HelloBundle/Entity/Company.php 

namespace Acme\HelloBundle\Entity; 

class Company 

{ 

    private $name; 

    private $website; 

    private $address; 

    private $zipcode; 

    private $city; 

    private $country; 

} 

 Customer實體：

// src/Acme/HelloBundle/Entity/Customer.php 

class Customer 

    private $firstName; 

    private $lastName; 

Like you can see, each entity shares a few of the same fields: address, zipcode, city, country.

正如您所見，每個實體都有着一些相同的表單域：address、zipcode、city和country。

Now, you want to build two forms: one for a Company and the second for a Customer.

現在，您要建立兩個表單：一個對應Company，第二個對應Customer。

Start by creating a very simple CompanyType and CustomerType:

首先建立一個非常簡單的CompanyType和CustomerType：

CompanyType類：

// src/Acme/HelloBundle/Form/Type/CompanyType.php 

namespace Acme\HelloBundle\Form\Type; 

use Symfony\Component\Form\FormBuilderInterface; 

class CompanyType extends AbstractType 

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

    { 

        $builder 

            ->add('name', 'text') 

            ->add('website', 'text'); 

    } 

 CustomerType類：

// src/Acme/HelloBundle/Form/Type/CustomerType.php 

class CustomerType extends AbstractType 

            ->add('firstName', 'text') 

            ->add('lastName', 'text'); 

Now, we have to deal with the four duplicated fields. Here is a (simple) location form type:

現在我們需要處理那四個重複的表單域。下面是個（簡單）的位置表單類型：

// src/Acme/HelloBundle/Form/Type/LocationType.php 

use Symfony\Component\OptionsResolver\OptionsResolverInterface; 

class LocationType extends AbstractType 

            ->add('address', 'textarea') 

            ->add('zipcode', 'text') 

            ->add('city', 'text') 

            ->add('country', 'text'); 

    public function setDefaultOptions(OptionsResolverInterface $resolver) 

        $resolver->setDefaults(array( 

            'virtual' => true 

        )); 

    public function getName() 

        return 'location'; 

We don't actually have a location field in each of our entities, so we can't directly link our LocationType to our CompanyType or CustomerType. But we absolutely want to have a dedicated form type to deal with location (remember, DRY!).

實際上在每個實體中我們并沒有location表單域，是以我們不能直接将LocationType鍊入我們的CompanyType或CustomerType中。但我們又絕對想要一個專門處理位置的表單類型（記住，DRY！）

The virtual form field option is the solution.

解決這個問題就需要用到虛拟表單域選項了。

We can set the option 'virtual' => true in the setDefaultOptions() method of LocationType and directly start using it in the two original form types.

我們可以在LocationType類中的setDefaultOptions()方法中将選項'virtual'設定為true，并且在兩個原始域類型中直接使用它。

Look at the result:

所下所示：

// CompanyType 

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

    $builder->add('foo', new LocationType(), array( 

        'data_class' => 'Acme\HelloBundle\Entity\Company' 

    )); 

// CustomerType 

    $builder->add('bar', new LocationType(), array( 

        'data_class' => 'Acme\HelloBundle\Entity\Customer' 

With the virtual option set to false (default behavior), the Form Component expects each underlying object to have a foo (or bar) property that is either some object or array which contains the four location fields. Of course, we don't have this object/array in our entities and we don't want it!

當virtual選項設為false時（預設值），表單元件期望每個相關的對象都有一個foo（或bar）屬性，要麼是一些對象，要麼是包含四個位置表單域的數組。當然，在我們的實體中沒有這樣的對象或數組，而且我們也不想那樣做！

With the virtual option set to true, the Form component skips the foo (or bar) property, and instead "gets" and "sets" the 4 location fields directly on the underlying object!

當virtual選項設為true時，表單元件忽略foo（或bar）屬性，取而代之的是在相關對象中直接"gets"和"sets"這4個位置表單域！

Instead of setting the virtual option inside LocationType, you can (just like with any options) also pass it in as an array option to the third argument of $builder->add().

如果不使用在LocationType中設定virtual選項，您也可以（如其它選項那樣）将其作為一個數組選項發送到$builder->add()的第三個參數。

本文轉自 firehare 51CTO部落格，原文連結：http://blog.51cto.com/firehare/1004587，如需轉載請自行聯系原作者