The article there discusses how to add an appointment only. We get the date by double-clicking on a CalendarItem and assigning it to the date of the appointment. If you want to add an appointment by other means, say through a button, it is possible. I am not really sure about your problem but is it about filtering the appointments? If so, you can add dependency properties to the custom control, like start and end date, or type of appointment. Use these dependency properties to filter what appointments you would like to show. Kindly correct me if I'm mistaken. Hope this helps.