今天一个问题, Attach,还真没记住
CDC *pDC = GetDC();
CBitmap BmpBack,BmpA,BmpB,*pOldBack,*pOldA,*pOldB;
HBITMAP hbitmap = (HBITMAP)LoadImage(NULL,"test.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
BmpBack.Attach(hbitmap);
CDC dcBack,dcA,dcB;
dcBack.CreateCompatibleDC(pDC);
pOldBack=dcBack.SelectObject(&BmpBack);
pDC->BitBlt(0,0,300,300,&dcBack,0,0,SRCCOPY); //画背景


dcBack.SelectObject(pOldBack);