How can I differentiate between the right and left shiftkey?

Question

C# give in the KeyDown-event the following keyword: Keys There you can find all keyboard-keys and also RShiftKey & LShiftKey! The e.KeyValue for the right one is 160 and left 161. But how can I differentiate between this keys? My C# recognize only both of them and shows me only the e.KeyValue of 16! :( On the other Hand: 16 is contains 160 and 161... - any idea?