Conditional data annotation

Question

Is there a way to make a data annotation conditional? I have a table Party where I store both organisations and persons. If I\'m adding an organisation I don\'t w

Answer 1

I know this topic has some time, but if you'd like to use only declarative validation for that, you could just use such a simple construction (see this reference for further possibilities):

[RequiredIf(DependentProperty = "party_type", TargetValue = "P")]
public string surname { get; set; }

public string party_type { get; set; }

Update:

Since the ExpressiveAnnotations 2.0, there is a breaking change. Now the same thing can be done in a simpler manner:

[RequiredIf("party_type == 'P'")]
public string surname { get; set; }