Hi, I have a .NET 2.0 class the properties of which are marked virtual.I need to use the class as a model in a MVC2 application. So, I have created a .NET 3.5 class inheriting from the .NET 2.0 class and added the DataAnnotations attributes to the overriden properties in the new class. A snippet of what I have done is below // .NET 2.0 class public class Customer { private string _firstName = ""; public virtual string FirstName { get { return _firstName; } set { _firstName = value; } } } // .NET 3.5 class public class MVCCustomer : Customer { [Required(ErrorMessage="Firstname is required")] public override string FirstName { get { return base.FirstName; } set { base.FirstName = value; } } } I have used the class as the model for a MVC2 view using the HtmlFor helpers. Serverside validation works correctly but the client side validation does not. Specifically the validation error is not displayed on the page. What am I missing, or is it only possible to do this using buddy classes. Thanks.