Public Event LostFocus As RoutedEventHandler

Dim instance As VirtualizingStackPanel
Dim handler As RoutedEventHandler
 
AddHandler instance.LostFocus, handler

public event RoutedEventHandler LostFocus

public event LostFocus: RoutedEventHandler; 

In JScript, you can handle the events defined by another class, but you cannot define your own.

public: __event RoutedEventHandler* LostFocus

public:
event RoutedEventHandler^ LostFocus