Fires before an item is added to the current DockLayoutManager object.
NuGet Package: DevExpress.Wpf.Docking
public event BeforeItemAddedEventHandler BeforeItemAdded
Public Event BeforeItemAdded As BeforeItemAddedEventHandler
The BeforeItemAdded event's data class is.
Handle the BeforeItemAdded event to specify actions to be performed immediately before an item (the BaseLayoutItem descendant) is added to the current DockLayoutManager. For instance, you might want an additional item validation to be performed before an item is added.