In Windows Presentation Foundation and Silverlight, the movement of an event in a tree of elements. There are three types of event routing: direct, bubbling, and tunneling. With direct routing, the event does not move in the tree. With bubbling, the event moves up to the top of the tree. With tunneling, the event starts at the top of the tree and moves down to the source of the event. In Silverlight, event routing and routed events are used, but tunneling is not implemented.