1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:

    public class ColoredComboBoxItem : ComboBoxItem
    {
        public bool Visited
        {
            get { return (bool)GetValue(VisitedProperty); }
            set { SetValue(VisitedProperty, value); }
        }

        // Using a DependencyProperty as the backing store for Visited.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty VisitedProperty =
               DependencyProperty.Register("Visited", typeof(bool), typeof(ColoredComboBoxItem), new UIPropertyMetadata(false));
    }