IsNull ====== Validates that a value is exactly equal to ``null``. To force that a property is blank (blank string or ``null``), see the :doc:`/reference/constraints/Blank` constraint. To ensure that a property is not null, see :doc:`/reference/constraints/NotNull`. Also see :doc:`NotNull `. ========== =================================================================== Applies to :ref:`property or method ` Options - `groups`_ - `message`_ - `payload`_ Class :class:`Symfony\\Component\\Validator\\Constraints\\IsNull` Validator :class:`Symfony\\Component\\Validator\\Constraints\\IsNullValidator` ========== =================================================================== Basic Usage ----------- 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: .. configuration-block:: .. code-block:: php-annotations // src/Entity/Author.php namespace App\Entity; use Symfony\Component\Validator\Constraints as Assert; class Author { /** * @Assert\IsNull */ protected $firstName; } .. code-block:: yaml # config/validator/validation.yaml App\Entity\Author: properties: firstName: - 'IsNull': ~ .. code-block:: xml .. code-block:: php // src/Entity/Author.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) { $metadata->addPropertyConstraint('firstName', Assert\IsNull()); } } Options ------- .. include:: /reference/constraints/_groups-option.rst.inc ``message`` ~~~~~~~~~~~ **type**: ``string`` **default**: ``This value should be null.`` This is the message that will be shown if the value is not ``null``. You can use the following parameters in this message: =============== ============================================================== Parameter Description =============== ============================================================== ``{{ value }}`` The current (invalid) value =============== ============================================================== .. include:: /reference/constraints/_payload-option.rst.inc