The GanttViewDataItem Collection Editor allows you to add tasks to the gantt view in design time.
The more important properties of the item you need to set up are:
Title: This is the text that will be displayed over the item if it is a Task item. No text is displayed for summary and milestone items.
Start: The start date and time for the task.
End: The end date and time for the task.
ReadOnly: Determines whether this item is editable.
Visible: Determines whether this item will be visible in RadGanttView.
ContextMenu: Allows you to assign a particular context menu to each individual item. Individual context menus are shown with higher priority than the default of the control’s context menu.
Progress: Allows you to set the completion of the task.