FluentValidator

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FluentValidation

Knowledge

  • The RuleFor method create a validation rule.

To specify a validation rule for a particular property, call the RuleFor method, passing a lambda expression that indicates the property that you wish to validate.

  • Rules are run syncronously

By default, all rules in FluentValidation are separate and cannot influence one another. This is intentional and necessary for asynchronous validation to work.

  • Must, NotNull…. are built-in validators. WithMessage is a method on a validator. When defines condition for validator(s).
  • Append multiple validators on a same property are called chaining validators.
  • Chainning Validators are executed by sequence. CascadeMode can define how these chaining validators are exectued. Continue is default which means even a validator fail, the latter validators will still be invoked. StopOnFirstFailure will stop at the first failure of these chaining validators.
  • When defines condition for validator(s)/rules. ApplyConditionTo.AllValidators is the default setting. ApplyConditionTo.CurrentValidator will make the condition only work to the preceding validator.

By default FluentValidation will apply the condition to all preceding validators in the same call to RuleFor