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100 lines
3.1 KiB
ReStructuredText
100 lines
3.1 KiB
ReStructuredText
IsNull
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======
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Validates that a value is exactly equal to ``null``. To force that a property
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is blank (blank string or ``null``), see the :doc:`/reference/constraints/Blank`
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constraint. To ensure that a property is not null, see :doc:`/reference/constraints/NotNull`.
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Also see :doc:`NotNull </reference/constraints/NotNull>`.
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========== ===================================================================
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Applies to :ref:`property or method <validation-property-target>`
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Class :class:`Symfony\\Component\\Validator\\Constraints\\IsNull`
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Validator :class:`Symfony\\Component\\Validator\\Constraints\\IsNullValidator`
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========== ===================================================================
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Basic Usage
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-----------
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If, for some reason, you wanted to ensure that the ``firstName`` property
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of an ``Author`` class exactly equal to ``null``, you could do the following:
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.. configuration-block::
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.. code-block:: php-attributes
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// src/Entity/Author.php
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namespace App\Entity;
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use Symfony\Component\Validator\Constraints as Assert;
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class Author
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{
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#[Assert\IsNull]
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protected ?string $firstName = null;
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}
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.. code-block:: yaml
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# config/validator/validation.yaml
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App\Entity\Author:
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properties:
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firstName:
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- 'IsNull': ~
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.. code-block:: xml
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<!-- config/validator/validation.xml -->
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<?xml version="1.0" encoding="UTF-8" ?>
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<constraint-mapping xmlns="http://symfony.com/schema/dic/constraint-mapping"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://symfony.com/schema/dic/constraint-mapping https://symfony.com/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">
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<class name="App\Entity\Author">
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<property name="firstName">
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<constraint name="IsNull"/>
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</property>
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</class>
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</constraint-mapping>
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.. code-block:: php
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// src/Entity/Author.php
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namespace App\Entity;
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use Symfony\Component\Validator\Constraints as Assert;
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use Symfony\Component\Validator\Mapping\ClassMetadata;
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class Author
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{
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// ...
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public static function loadValidatorMetadata(ClassMetadata $metadata): void
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{
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$metadata->addPropertyConstraint('firstName', Assert\IsNull());
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}
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}
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Options
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-------
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.. include:: /reference/constraints/_groups-option.rst.inc
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``message``
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~~~~~~~~~~~
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**type**: ``string`` **default**: ``This value should be null.``
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This is the message that will be shown if the value is not ``null``.
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You can use the following parameters in this message:
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=============== ==============================================================
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Parameter Description
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=============== ==============================================================
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``{{ value }}`` The current (invalid) value
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``{{ label }}`` Corresponding form field label
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=============== ==============================================================
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.. include:: /reference/constraints/_payload-option.rst.inc
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