A milestone is a significant point or landmark in your project. Milestones are created as tasks with zero duration and are visualized with a diamond shape. The milestone’s shape and color are customizable. Additionally text can appear to the left, right, top, or bottom of the milestone marker. To create a milestone you can use the Duration property of the Task class and set its value to zero.

To create a milestone at design time, follow the steps below:

1. Select the C1GanttView control and click on its smart tag to open the C1GanttView Tasks menu.
2. Select Edit Tasks. The C1GanttView.Tasks Collection Editor appears.
3. Click Add to add a task to the Members list.
4. Enter the Name, Start date and Finish date for the task.
5. Set the Duration to 0.