How do you use Castle Validator with Subsonic generated classes?

Question

Castle Validator uses attributes to specify validation rules. How can you hook these up with Subsonic's generated classes (or any classes where you can't define the attributes on)? Is there a way to programatically specify validation rules without using the attribute method?

Answer 1

There are a few ways to do this - attributes is the lowest friction option, but obviously doesn't deal well with generated code or validation of multiple properties better expressed in code.

Take a look at the following link for some indications on how to do this blog post: Castle Validator Enhancements

If you have a look at the castle source code these are some good starting points:

• IValidationContributor interface
• DefaultValidationPerformer class

Hope that helps.

Answer 2

I think the best way to do that is using MetadataType. It's a DataAnnotations that let's your class have like a pair or something like that. I don't know how to explain it better so, let's for the samples:

You first need to add this directive to your code:

using System.ComponentModel.DataAnnotations;

Them you should create the partial class of you generated class with an attribute specifying that this class has an MetadataType:

[MetadataType(typeof(UserMetadata))] 
public partial class User
{
}

Then you create your metadata class with your castle validation:

public class UserMetadata
{
    [ValidateNonEmpty]
    [ValidateLength(6, 24)]
    public string Username { get; set; }

    [ValidateNonEmpty]
    [ValidateLength(6, 100)]
    [ValidateEmail]
    public string Email { get; set; }

    [ValidateNonEmpty]
    [ValidateLength(6, 24)]
    public string Password { get; set; }
}

Hope it helps