protected virtual void OnPropertyChanged(
	string propertyName = null
)

Protected Overridable Sub OnPropertyChanged ( 
	Optional propertyName As String = Nothing
)

protected:
virtual void OnPropertyChanged(
	String^ propertyName = nullptr
)

abstract OnPropertyChanged : 
        ?propertyName : string 
(* Defaults:
        let _propertyName = defaultArg propertyName null
*)
-> unit 
override OnPropertyChanged : 
        ?propertyName : string 
(* Defaults:
        let _propertyName = defaultArg propertyName null
*)
-> unit