public SalaryValidator() { FluentValidator.RuleFor(x => x.FirstName).NotEmpty().WithName(Resources.FirstNameText); FluentValidator.RuleFor(x => x.LastName).NotEmpty().WithName(Resources.LastNameText); FluentValidator.RuleFor(x => x.BirthDate).NotEmpty().WithName(Resources.BirthDateText); FluentValidator.Custom(delegate(ISalary x) { if (string.IsNullOrEmpty(x.FirstName)) { return(new ValidationFailure(string.Empty, "IMIĘ NIE MOŻE BY PUSTE")); } return(null); }); }