Hello Min,

Thank you for posting in our forum.

Right now UltraDayView does not expose a property or method allowing you to disable particular time slot. However you can achieve this by applying some custom appearance to the time slots you need. Then, depending of your application scenario you may need to handle some events. For example:

• If you do not want the disabled slots to be selectable you may handle BeforeTimeSlotSelectionChanged. In the event handler you will need to check if the new time slot is in the disabled interval. If so cancel the event;

• If you do not want the user to be able to add appointment to disabled slots you may handle BeforeDisplayAppointmentDialog of the UltraCalendarInfo. If the appointment is in the disabled time slot cancel the event.

In the attached sample project I have implement this approach. Please check my sample and let me know if this is what you are looking for of if I am missing something.