ViewModel validation for a List

Question

I have the following viewmodel definition

public class AccessRequestViewModel
{
    public Request Request { get; private set; }
    public SelectList Buildi         


        

Answer 1

It would be very clean and elegant to have a custom validation. Something like this:

public class AccessRequestViewModel
{
    public Request Request { get; private set; }
    public SelectList Buildings { get; private set; }
    [AtLeastOneItem]
    public List<Person> Persons { get; private set; }
}

Or [MinimumItems(1)].