Choice

编辑此页

此约束用于确保给定值是一组给定的有效选项之一。它也可以用于验证项目数组中的每个项目是否是这些有效选项之一。

适用于	属性或方法
类	Choice
验证器	ChoiceValidator

基本用法

此约束的基本思想是，您为其提供一组有效值（可以通过多种方式完成），并且它验证给定属性的值是否存在于该数组中。

如果您的有效选项列表很简单，则可以直接通过 choices 选项传入它们

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        // src/Entity/Author.php
namespace App\Entity;

use Symfony\Component\Validator\Constraints as Assert;

class Author
{
    public const GENRES = ['fiction', 'non-fiction'];

    #[Assert\Choice(['New York', 'Berlin', 'Tokyo'])]
    protected string $city;

    #[Assert\Choice(choices: Author::GENRES, message: 'Choose a valid genre.')]
    protected string $genre;
}
    

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        # config/validator/validation.yaml
App\Entity\Author:
    properties:
        city:
            - Choice: [New York, Berlin, Tokyo]
        genre:
            - Choice:
                choices:  [fiction, non-fiction]
                message:  Choose a valid genre.
    

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        <!-- config/validator/validation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<constraint-mapping xmlns="https://symfony.ac.cn/schema/dic/constraint-mapping"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="https://symfony.ac.cn/schema/dic/constraint-mapping https://symfony.ac.cn/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">

    <class name="App\Entity\Author">
        <property name="city">
            <constraint name="Choice">
                <value>New York</value>
                <value>Berlin</value>
                <value>Tokyo</value>
            </constraint>
        </property>
        <property name="genre">
            <constraint name="Choice">
                <option name="choices">
                    <value>fiction</value>
                    <value>non-fiction</value>
                </option>
                <option name="message">Choose a valid genre.</option>
            </constraint>
        </property>
    </class>
</constraint-mapping>
    

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        // src/EntityAuthor.php
namespace App\Entity;

use Symfony\Component\Validator\Constraints as Assert;
use Symfony\Component\Validator\Mapping\ClassMetadata;

class Author
{
    // ...

    public static function loadValidatorMetadata(ClassMetadata $metadata): void
    {
        $metadata->addPropertyConstraint(
            'city',
            new Assert\Choice(['New York', 'Berlin', 'Tokyo'])
        );

        $metadata->addPropertyConstraint('genre', new Assert\Choice([
            'choices' => ['fiction', 'non-fiction'],
            'message' => 'Choose a valid genre.',
        ]));
    }
}
    

使用回调函数提供选项

您还可以使用回调函数来指定您的选项。如果您想将选项保存在某个中心位置，以便例如，您可以访问这些选项以进行验证或构建选择表单元素，这将非常有用

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        // src/Entity/Author.php
namespace App\Entity;

class Author
{
    public static function getGenres(): array
    {
        return ['fiction', 'non-fiction'];
    }
}
    

您可以将此方法的名称传递给 Choice 约束的 callback 选项。

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        // src/Entity/Author.php
namespace App\Entity;

use Symfony\Component\Validator\Constraints as Assert;

class Author
{
    #[Assert\Choice(callback: 'getGenres')]
    protected string $genre;
}
    

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        # config/validator/validation.yaml
App\Entity\Author:
    properties:
        genre:
            - Choice: { callback: getGenres }
    

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        <!-- config/validator/validation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<constraint-mapping xmlns="https://symfony.ac.cn/schema/dic/constraint-mapping"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="https://symfony.ac.cn/schema/dic/constraint-mapping https://symfony.ac.cn/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">

    <class name="App\Entity\Author">
        <property name="genre">
            <constraint name="Choice">
                <option name="callback">getGenres</option>
            </constraint>
        </property>
    </class>
</constraint-mapping>
    

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        // src/EntityAuthor.php
namespace App\Entity;

use Symfony\Component\Validator\Constraints as Assert;
use Symfony\Component\Validator\Mapping\ClassMetadata;

class Author
{
    // ...

    public static function loadValidatorMetadata(ClassMetadata $metadata): void
    {
        $metadata->addPropertyConstraint('genre', new Assert\Choice([
            'callback' => 'getGenres',
        ]));
    }
}
    

如果回调是在不同的类中定义的并且是静态的，例如 App\Entity\Genre，则可以将类名和方法作为数组传递。

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        // src/Entity/Author.php
namespace App\Entity;

use App\Entity\Genre;
use Symfony\Component\Validator\Constraints as Assert;

class Author
{
    #[Assert\Choice(callback: [Genre::class, 'getGenres'])]
    protected string $genre;
}
    

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        # config/validator/validation.yaml
App\Entity\Author:
    properties:
        genre:
            - Choice: { callback: [App\Entity\Genre, getGenres] }
    

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        <!-- config/validator/validation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<constraint-mapping xmlns="https://symfony.ac.cn/schema/dic/constraint-mapping"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="https://symfony.ac.cn/schema/dic/constraint-mapping https://symfony.ac.cn/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">

    <class name="App\Entity\Author">
        <property name="genre">
            <constraint name="Choice">
                <option name="callback">
                    <value>App\Entity\Genre</value>
                    <value>getGenres</value>
                </option>
            </constraint>
        </property>
    </class>
</constraint-mapping>
    

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        // src/Entity/Author.php
namespace App\Entity;

use App\Entity\Genre;
use Symfony\Component\Validator\Constraints as Assert;
use Symfony\Component\Validator\Mapping\ClassMetadata;

class Author
{
    // ...

    public static function loadValidatorMetadata(ClassMetadata $metadata): void
    {
        $metadata->addPropertyConstraint('genre', new Assert\Choice([
            'callback' => [Genre::class, 'getGenres'],
        ]));
    }
}
    