RuleSets

RuleSets allow you to group validation rules together which can be executed together as a group whilst ignoring other rules:

For example, let’s imagine we have 3 properties on a Person object (Id, Surname and Forename) and have a validation rule for each. We could group the Surname and Forename rules together in a “Names” RuleSet:

 public class PersonValidator : AbstractValidator<Person> {
  public PersonValidator() {
     RuleSet("Names", () => {
        RuleFor(x => x.Surname).NotNull();
        RuleFor(x => x.Forename).NotNull();
     });

     RuleFor(x => x.Id).NotEqual(0);
  }
}

Here the two rules on Surname and Forename are grouped together in a “Names” RuleSet. We can invoke only these rules by passing additional options to the Validate method:

var validator = new PersonValidator();
var person = new Person();
var result = validator.Validate(person, options => options.IncludeRuleSets("Names"));

This allows you to break down a complex validator definition into smaller segments that can be executed in isolation. If you call Validate without passing a ruleset then only rules not in a RuleSet will be executed.

You can execute multiple rulesets by passing multiple ruleset names to IncludeRuleSets:

var result = validator.Validate(person, options => {
  options.IncludeRuleSets("Names", "MyRuleSet", "SomeOtherRuleSet");
});

You can also include all the rules not part of a ruleset by using calling IncludeRulesNotInRuleSet, or by using the special name “default” (case insensitive):

validator.Validate(person, options => {
  // Option 1: IncludeRulesNotInRuleSet is the equivalent of using the special ruleset name "default"
  options.IncludeRuleSets("Names").IncludeRulesNotInRuleSet();
  // Option 2: This does the same thing.
  option.IncludeRuleSets("Names", "default");
});

This would execute rules in the MyRuleSet set, and those rules not in any ruleset. Note that you shouldn’t create your own ruleset called “default”, as FluentValidation will treat these rules as not being in a ruleset.

You can force all rules to be executed regardless of whether or not they’re in a ruleset by calling IncludeAllRuleSets (this is the equivalent of using IncludeRuleSets("*") )

validator.Validate(person, options => {
  options.IncludeAllRuleSets();
});

Note

The syntax above using the “options” callback is only available in FluentValidation 9.1 and newer. If you are using FluentValidation 9.0 and older, please read the section below.

RuleSets in FluentValidation 9.0 (or older)

Warning

The syntax in this section is deprecated and will be removed in FluentValidation 10.

Invoking RuleSets in FluentValidation 9.0 and older requires the use of a slightly different syntax, by passing the ruleset names to a named ruleSet parameter:

var validator = new PersonValidator();
var person = new Person();
var result = validator.Validate(person, ruleSet: "Names");

This is the equivalent of the first example above which executes a single ruleset.

You can execute multiple rulesets by using a comma-separated list of strings:

validator.Validate(person, ruleSet: "Names,MyRuleSet,SomeOtherRuleSet")

You can also include all the rules not part of a ruleset by using the special name “default” (case insensitive):

validator.Validate(person, ruleSet: "default,MyRuleSet")

This would execute rules in the MyRuleSet set, and those rules not in any ruleset. Note that you shouldn’t create your own ruleset called “default”, as FluentValidation will treat these rules as not being in a ruleset.

You can force all rules to be executed regardless of whether or not they’re in a ruleset by specifying a ruleset of “*”:

validator.Validate(person, ruleSet: "*")