Stop Fluent Validation on first failure

Question

i\'m defining a validation for my Request objects. I would like the validator to stop on the very first failure, not only the one on the same chain. In the example below, if my

Answer 1

Just check for null before running the rules that depend on them, using a When condition.

this.CascadeMode = CascadeMode.StopOnFirstFailure;
RuleFor(x => x.TechnicalHeader).NotNull().WithMessage("Header cannot be null");

// Ensure TechnicalHeader is provided
When(x => x.TechnicalHeader != null, () => {
    RuleFor(x => x.TechnicalHeader.Userid).NotEmpty().WithMessage("Userid cannot be null or an empty string");
    RuleFor(x => x.TechnicalHeader.CabCode).GreaterThan(0).WithMessage("CabCode cannot be or less than 0");
    RuleFor(x => x.TechnicalHeader.Ndg).NotEmpty().WithMessage("Ndg cannot be null or an empty string");
});