public SelectedDatesCollection(KellCalendar owner, SelectedDatesCollection dates) : this(owner)
        {
            if (owner == null)
            {
                throw new ArgumentNullException("owner");
            }

            this.owner = owner;

            this.Add(dates);
        }
        public void Add(SelectedDatesCollection dates)
        {
            if (dates == null)
            {
                throw new ArgumentNullException("dates");
            }

            for (int i = 0; i < dates.Count; i++)
            {
                this.Add(dates[i]);
            }
        }