The CustomCalendar.WorkWeeks Collection Editor is used for adding, removing, or modifying work weeks for the custom calendars at design time.
Right-click on the C1GanttView control and select Edit Calendars from its context menu. The C1GanttView.CustomCalendars Collection Editor appears. Click Add to add a new member to the collection. In the properties pane click on the ellipsis button next to WorkWeeks. The CustomCalendar.CalendarWorkWeeks Collection Editor appears like the following when a member is added to the collection:
