Fluent validation custom check from App constants

Question

How to validate if Status exists in my static class?

public static class AppConstants
{
    public static class FormStatus
    {
        public static string NEW = "New";
        public static string COMPLETE = "Complete";
        public static string DELETED = "Deleted";
    }
}

Validator class

public SetStatusCommandValidator(IApplicationDbContext context)
{
    _context = context;

    RuleFor(v => v.Status)
        .NotNull()
        .NotEmpty().WithMessage("Status is required.")
        .Must(???).WithMessage("Status is not a valid.");
}

Basically, how do I validate that the status' values must be one of the AppConstants.FormStatus?

Thanks!

Answer 1

You can create a collection / array inline in the Must predicate and use .Contains :

RuleFor(v => v.Status)
    .NotNull()
    .NotEmpty().WithMessage(...)
    .Must(v => new [] { AppConstants.FormStatus.NEW, AppConstants.FormStatus.COMPLETE, AppConstants.FormStatus.DELETED }.Contains(v)).WithMessage(...);

Alternatively, you can add another property to FormStatus that contains all of them:

public static class AppConstants
{
    public static class FormStatus
    {
        // Statuses here

        public static string[] ALL_STATUSES = new string[] { NEW, COMPLETE, DELETED };
    }
}

Then your Must predicate becomes Must(v => AppConstants.FormStatus.ALL_STATUSES.Contains(v)).WithMessage(...);

Sorry if the syntax isn't exactly right and doesn't compile right away, I wrote it on my phone with no way to double check it.

Answer 2

Since you're not using an Enum (which would allow you to use .IsEnumName() ), I think you need to create a custom validator function:

private bool BeAValidStatus(string status) 
{
    return typeof(AppConstants.FormStatus)
        .GetFields(BindingFlags.Static | BindingFlags.Public)
        .Where(f => f.GetRawConstantValue() == status)
        .Any();
}

Then use the custom function in a rule:

RuleFor(v => v.Status)
        .NotNull()
        .NotEmpty().WithMessage("Status is required.")
        .Must(BeAValidStatus).WithMessage("Status is not a valid.");