Question

I have a ViewModel. something like this

public class ViewModel
{
   public int Id { get; set; }
   public int? Value { get; set; }
}

I have a table of existing ViewModels, and below that I have a form where you can add a new ViewModel

For existing ViewModels that are fetched from DB i want no validation on the Value property, but for the case when adding a new ViewModel I want required validation…. The real model is more complex then this one so I want to use the same model in both cases.. Is it possible?

edit: this works

public class AddNewViewModel : ViewModel
{
    public new int Value { get; set; }
}

Is it better to use new or virtual/override and why?

Answer 1

Required attributes are compiled into the class. You could do something like this:

public class BaseViewModel
{
   public int Id { get; set; }
   public virtual int? Value { get; set; }
}

public class CreateViewModel : BaseViewModel
{
   [Required]
   public override int? Value { get; set; }
}

This way, you only add the validation attribute to the properties where you need them.