Pro WPF in C# 2010: Windows Presentation Foundation in .NET 4

5.5. Mouse Input

Mouse events perform several related tasks. The most fundamental mouse events allow you to react when the mouse is moved over an element. These events are MouseEnter (which fires when the mouse pointer moves over the element) and MouseLeave (which fires when the mouse pointer moves away). Both are direct events, which means they don't use tunneling or bubbling. Instead, they originate in one element and are raised by just that element. This makes sense because of the way controls are nested in a WPF window.

For example, if you have a StackPanel that contains a button and you move the mouse pointer over the button, the MouseEnter event will fire first for the StackPanel (once you enter its borders) and then for the button (once ...