Gets or sets a value that indicates the present state of the event handling for a routed event as it travels the route.
Assembly: System.Windows (in System.Windows.dll)
If you read this value from event data, true indicates that a handler along the event route has already marked this event as handled. A value of false indicates that no handler has marked the event as handled. However, the value should not typically be true for reading purposes. Handlers that are attached for an already handled event are not invoked by routing through the Windows Phone event system and therefore, cannot transmit event data to handlers.
Events that use DragEventArgs event data cannot have handlers attached that are invoked even when another handler marks as true. This is because AddHandler requires a RoutedEvent identifier, and the events that use DragEventArgs do not expose such an identifier.