Public Sub OnEvent( _
   ByVal source As TSource, _
   ByVal eventArgs As TEventArgs _
) 

Dim instance As WeakEventListener(Of TInstance,TSource,TEventArgs)
Dim source As TSource
Dim eventArgs As TEventArgs
 
instance.OnEvent(source, eventArgs)

public void OnEvent( 
   TSource source,
   TEventArgs eventArgs
)

public procedure OnEvent( 
    source: TSource;
    eventArgs: TEventArgs
); 

public function OnEvent( 
   source : TSource,
   eventArgs : TEventArgs
);

public: void OnEvent( 
   TSource* source,
   TEventArgs* eventArgs
) 

public:
void OnEvent( 
   TSource^ source,
   TEventArgs^ eventArgs
)