Order of DependentRules in FluentValidation

Question

I have the model like

public class Command : IRequest<bool>
{
    public int Id { get; set; }
    public int LabelId { get; set; }
    public int UserId { get; set; }
}

And fluent validator

public class Validator : AbstractValidator<Command>
{
    public Validator(DbContext dbContext)
    {
        RuleFor(q => q.LabelId).GreaterThan(0);
        RuleFor(q => q.UserId).GreaterThan(0);
        RuleFor(q => q.Id).GreaterThan(0);
        RuleFor(t => t.Id).GreaterThan(0).DependentRules(() =>
            RuleFor(q => q.Id).SetValidator(new EntityExistsValidator(dbContext)));
    }
}

where EntityExistsValidator is custom PropertyValidator that makes call to database to check if entity exists.

How can I call this validator only when all rules applied and model is valid?

Example

Property  |  Value |  `EntityExistsValidator` run
-------------------------------------------------
LabelId   |    0   |  no
UserId    |    0   |  no
Id        |    0   |  no

so, it should not run when validation is fail. Only when model is valid. How can I achieve that?

Answer 1

My suggestion would be to use a PreValidator class`:

public class Validator : AbstractValidator<Command>
{
    private class PreValidator : AbstractValidator<Command>
    {
        internal PreValidator()
        {
            RuleFor(q => q.LabelId).GreaterThan(0);
            RuleFor(q => q.UserId).GreaterThan(0);
            RuleFor(q => q.Id).GreaterThan(0);
        }
    }

    public Validator(DbContext dbContext)
    {
        RuleFor(x => x)
          .SetValidator(new PreValidator())
          .DependentRules(() => RuleFor(q => q.Id)
              .SetValidator(new EntityExistsValidator(dbContext)));
    }
}