Creates a new item in a NavBarControl and creates a link to this item in the current group.
A NavBarItemLink object representing the link to the item being created.
This method creates a new item in a NavBarControl and then adds a link to the item in the current group. The link is added to the end of the NavBarGroup.ItemLinks collection. The methods provided by the NavBarGroup.ItemLinks collection allow you to add links to existing items. All the NavBarControl's items are stored in the NavBarControl.Items collection.
If a group does not belong to a NavBarControl, the AddItem method does nothing and returns null.
For more information on items and links, see Navigation Bar.