Hi Terry Newton,
Thank you for contacting us!
You have begun in a right direction extending the Appointment class with your own property telling whether it is visible/invisible. However, to tell the AppointmentItem
to depend on it, you will need to bind its Visibility
property to the new property of your custom appointment via a converter. This, unfortunately, is only achievable through creating a custom theme (here
is some info regarding WPF - it is the same as Silverlight).
Another way to accomplish your goal, as you have already spotted, and as I think better, is to support two collections of appointments. One will contain all of your appointments, and the other - the appointments you need to see in a certain moment.
Hope this explains the situation. Should you need further help, do not hesitate to contact us.
the Telerik team