New Post: ValidationResultHolder - Rule Dependency

Hi Guys,

In my project I need to implement a conditional variable to a Rule. Imagine, Rule B can only run if the Rule A does not fail, How do you achieve it today? What I've done is, I created a class called ValidationResultHolder and inside this class a property IsValid. Then In my property validator extension I pass it in the constructor and get the result after the Rule is executed. For example:

            var validVehicle = new ValidationResultHolder();

            RuleFor(v => v)
                .MustBeAValidVehicle(validVehicle)
                .WithName("Vehicle")
                .Unless(v => v.MakeId == null || v.ModelId == null && v.Year == default(short));            

            RuleFor(v => v.VehicleVin)
                .MustBeAValidVehicleVin()                
                .When(v => validVehicle.IsValid);

In addition I downloaded the source code and added an overload for each default property validator which is implemented.

public static IRuleBuilderOptions<T, TProperty> NotNull<T, TProperty>(this IRuleBuilder<T, TProperty> ruleBuilder, ValidationResultHolder valid)
        {
            return ruleBuilder.SetValidator(new NotNullValidator(valid));
        }

public class NotNullValidator : PropertyValidator, INotNullValidator {
        readonly ValidationResultHolder validationResultHolder;

        public NotNullValidator()
            : base(() => Messages.notnull_error)
        {
            validationResultHolder = new ValidationResultHolder();
        }

        public NotNullValidator(ValidationResultHolder valid)
            : base(() => Messages.notnull_error)
        {
            validationResultHolder = valid;
        }

        protected override bool IsValid(PropertyValidatorContext context)
        {
            validationResultHolder.IsValid = context.PropertyValue != null;

            return validationResultHolder.IsValid;
        }
    }

I think it should be considered as a new feature to Fluent Validation.