FluentValidation rule for multiple properties

Question

I have a FluentValidator that has multiple properties like zip and county etc. I want to create a rule that takes two properties just like a RuleFor construct

Answer 1

In my case I needed to mark a property as required (x.RequiredProperty in the example below) if another property was not null (x.ParentProperty in the example below). I ended up using the When syntax:

RuleFor(x => x.RequiredProperty).NotEmpty().When(x => x.ParentProperty != null);

Or if you have more then one rule for a common when clause you can write it as follows:

When(x => x.ParentProperty != null, () =>
{
    RuleFor(x => x.RequiredProperty).NotEmpty();
    RuleFor(x => x.OtherRequiredProperty).NotEmpty();
});

The definition of the When syntax is the following:

/// 

/// Defines a condition that applies to several rules
/// 
/// The condition that should apply to multiple rules
/// Action that encapsulates the rules.
/// 
public IConditionBuilder When (Func predicate, Action action);