发布于 2015-08-27 16:47:19 | 177 次阅读 | 评论: 0 | 来源: 网络整理
Validates that a value is exactly equal to null. To force that a property
is simply blank (blank string or null), see the Blank
constraint. To ensure that a property is not null, see NotNull.
| Applies to | property or method |
| Options | |
| Class | Null |
| Validator | NullValidator |
If, for some reason, you wanted to ensure that the firstName property
of an Author class exactly equal to null, you could do the following:
# src/Acme/BlogBundle/Resources/config/validation.yml
AcmeBlogBundleEntityAuthor:
properties:
firstName:
- 'Null': ~
// src/Acme/BlogBundle/Entity/Author.php
namespace AcmeBlogBundleEntity;
use SymfonyComponentValidatorConstraints as Assert;
class Author
{
/**
* @AssertNull()
*/
protected $firstName;
}
<!-- src/Acme/BlogBundle/Resources/config/validation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<constraint-mapping xmlns="http://symfony.com/schema/dic/constraint-mapping"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://symfony.com/schema/dic/constraint-mapping http://symfony.com/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">
<class name="AcmeBlogBundleEntityAuthor">
<property name="firstName">
<constraint name="Null" />
</property>
</class>
</constraint-mapping>
// src/Acme/BlogBundle/Entity/Author.php
namespace AcmeBlogBundleEntity;
use SymfonyComponentValidatorMappingClassMetadata;
use SymfonyComponentValidatorConstraints as Assert;
class Author
{
public static function loadValidatorMetadata(ClassMetadata $metadata)
{
$metadata->addPropertyConstraint('firstName', AssertNull());
}
}
警告
When using YAML, be sure to surround Null with quotes ('Null')
or else YAML will convert this into a null value.
type: string default: This value should be null.
This is the message that will be shown if the value is not null.
type: mixed default: null
2.6 新版功能: The payload option was introduced in Symfony 2.6.
This option can be used to attach arbitrary domain-specific data to a constraint. The configured payload is not used by the Validator component, but its processing is completely up to.
For example, you may want to used several error levels to present failed constraint differently in the front-end depending on the severity of the error.