LostFocusEventManager Class
Provides a WeakEventManager implementation so that you can use the "weak event listener" pattern to attach listeners for the UIElement.LostFocus or ContentElement.LostFocus events.
Assembly: PresentationFramework (in PresentationFramework.dll)
In order to be listeners in this pattern, your listener objects must implement IWeakEventListener. You do not need to implement IWeakEventListener on the class that is the source of the events.
WPF data binding uses this WeakEventManager so that internal classes that update bindings can attach listeners for a UIElement.LostFocus or ContentElement.LostFocus event on an object that is the target of a binding. This supports notification for the LostFocus mode of data binding, without creating strong references to data binding targets.
System.Windows.Threading.DispatcherObject
System.Windows.WeakEventManager
System.Windows.LostFocusEventManager
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.