Symfony2CookBook：如何使用虛擬表單域選項

• 原文出處：http://symfony.com/doc/2.1/cookbook/form/use_virtuals_forms.html
• 原文作者：symfony.com
• 授權許可：創作共用協議
• 翻譯人員：FireHare
• 校對人員：FireHare
• 適用版本：Symfony 2.1
• 文章狀態：草譯階段

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，虛擬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 
  
namespace Acme\HelloBundle\Entity; 
  
 
  
class Customer 
  
{ 
  
    private $firstName; 
  
    private $lastName; 
  
 
  
    private $address; 
  
    private $zipcode; 
  
    private $city; 
  
    private $country; 
  
} 
 

Like you can see, each entity shares a few of the same fields: address, zipcode, city, country.
正如您所見，每個實體都有著一些相同的表單域：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 
  
namespace Acme\HelloBundle\Form\Type; 
  
 
  
use Symfony\Component\Form\FormBuilderInterface; 
  
 
  
class CustomerType extends AbstractType 
  
{ 
  
    public function buildForm(FormBuilderInterface $builder, array $options) 
  
    { 
  
        $builder 
  
            ->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 
  
namespace Acme\HelloBundle\Form\Type; 
  
 
  
use Symfony\Component\Form\FormBuilderInterface; 
  
use Symfony\Component\OptionsResolver\OptionsResolverInterface; 
  
 
  
class LocationType extends AbstractType 
  
{ 
  
    public function buildForm(FormBuilderInterface $builder, array $options) 
  
    { 
  
        $builder 
  
            ->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並沒有location表單域，因此我們不能直接將LocationType鏈入我們的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擬表單域選項了。

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()方法中將選項'virtual'設定為true，並且在兩個原始域類型中直接使用它。

Look at the result:
所下所示：

CompanyType類：

 

  
// CompanyType 
  
public function buildForm(FormBuilderInterface $builder, array $options) 
  
{ 
  
    $builder->add('foo', new LocationType(), array( 
  
        'data_class' => 'Acme\HelloBundle\Entity\Company' 
  
    )); 
  
} 
 

 CustomerType類：

 

  
// CustomerType 
  
public function buildForm(FormBuilderInterface $builder, array $options) 
  
{ 
  
    $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），表單組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，表單組件忽略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 $builder->add(). 如果不使用在LocationType中設定virtual選項，您也可以如其它選項那樣）將其作為一個數組選項發送到$builder->add()的第三個參數。