一个双缓冲问题

void CMnView::OnMouseMove(UINT nFlags, CPoint point) 

{

	CDC *pdc=this->GetDC();

	CDC   MenDC;   

	CBitmap   bm;

		

	CRect rt;

	GetClientRect(&rt);

	MenDC.CreateCompatibleDC(pdc);   

	bm.CreateCompatibleBitmap(pdc,rt.Width(),rt.Height());   

	MenDC.SelectObject(&bm);

	MenDC.FillSolidRect(0,0,rt.Width(),rt.Height(),RGB(255,255,255)); //用白色清屏

	//-------------------------------------------------------------------

	//这里用MenDC绘图即可

	//-------------------------------------------------------------------

	pdc->BitBlt(0,0,rt.Width(),rt.Height(),&MenDC,0,0,SRCCOPY);   //从内存DC考到屏幕DC 你说的模式是指SRCCOPY么？？

	MenDC.DeleteDC();   

	bm.DeleteObject();

	ReleaseDC(pdc);

	CScrollView::OnMouseMove(nFlags, point);

}