You must draw the new information you want to display on the screen on the memory DC.
The whole point of the code is that you needed some part of the GUI to show updated information, was it not?
I'm afraid not. It seems to be german or something such.Do you know what the following language in red is/means
But between BeginPaint and EndPaint is where you put your drawing code for drawing on the window. That's probably where you'll want to blit your memory DC to the window.