I plan to double buffer drawing the following pseudo code:
Excuse me: how to realize the screenshots from the screen, and save to memory (bmpMBoard) in the figure, before I was ready to redraw the window screenshot, redraw the corresponding back,

 
CLientDC XXDC (this) 
Graphics memGraphics; 
Bitmap bmpMBoard (XXXWidth XXXHeigh); 
Graphics memGraphics (& amp; BmpMBoard); 
Graphics scrGraphics (screenDC - & gt; GetSafeHdc ()); 

///drawing 

///

//output 
MemGraphics. XXXXXXX 
///
ScrGraphics. DrawImage (& amp; BmpMBoard, 0, 0)