Model binding dynamic collections. V AddableThing

gistfile1.cs

public class AddableThing
{
    public AddableThing() { }
    public AddableThing(Thing from)
    {
        Number = from.Number;
        Text = from.Text;
        IsEven = (from.Number % 2) == 0;
    }

    public string Text { get; set; }
    public int Number { get; set; }
    public bool IsEven { get; private set; }


    // mapping allowances...
}