Question

In the MSDN article Understanding Routed Events and Commands In WPF, it states

an event will bubble (propagate) up the visual tree from the source element until either it has been handled or it reaches the root element.

However, in this example, when you click the button, it doesn’t ‘bubble up the visual tree’ to get handled by the parent StackPanel event, i.e. clicking on the button fires no event.

Why not? What do they mean then by ‘bubbling up’ if not this?

XAML:

<Window x:Class='TestClickEvents456.Window1'     xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'     xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'     Title='Window1' Height='300' Width='300'>     <StackPanel x:Name='TheStackPanel'                 Background='Yellow'                 MouseDown='TheStackPanel_MouseDown'>         <Button x:Name='TheButton'                 Margin='10'                 Content='Click This'/>         <TextBlock x:Name='TheMessage'                    Text='Click the button or the yellow area'/>     </StackPanel> </Window> 

code-behind:

using System.Windows; using System.Windows.Input;  namespace TestClickEvents456 {     public partial class Window1 : Window     {         public Window1()         {             InitializeComponent();         }          private void TheStackPanel_MouseDown(object sender, MouseButtonEventArgs e)         {             TheMessage.Text = 'StackPanel was clicked.';         }      } } 

Answer 1

The event bubbles up, until it gets handled…

Since the Button does something with your mouse clicks, it absorbs your mouse event and turns it into a ClickEvent.

If you use the PreviewMouseDown, you see that the StackPanel first receives the event before the button does.. Preview events use the Tunnel down approach..