A More Thorough Discussion: Introducing the Routed Events
WPF introduces a revolutionary way to generate and handle events, known as routed events. When a user’s interface element generates an event, the event passes along through the entire Visual Tree, rethrowing the event for each element in the tree. The WPF runtime can then understand what element first generated the event that is the actual handled event. Event handlers whose job is managing a routed event must include an object of type
System.Windows.RoutedEventArgs in their signature. For a better understanding, consider the following basic XAML code that implements three buttons:
<StackPanel Button.Click="OnClick"> <Button Width="100" Height="30" Content="Button ...