Drawing flicker free line

In delphi there was a ability to redraw a line in xor mode ,in this mode pen merged with backcolor and caused to hide th开发者_StackOverflow社区e line,and if we had many color in background the line redrew with that color,how can i do same thing in c#, i don't wanna redraw line with backcolor again to hide line also i should say i want to draw line in panel mousemove event to connect one rectangle shape to another

In the .net world, you basically redraw the backcolor and redraw your line. You can use DoubleBuffering to help minimize the flickering.

If you are dead set on trying to go old school, look into the SetRop2 api call.