绘图后的虚框怎么取消

void CGraphicView::OnLButtonUp(UINT nFlags, CPoint point) 

{

  // TODO: Add your message handler code here and/or call default

  m_bDraw=FALSE;

  CClientDC dc(this);



  dc.SetROP2(R2_XORPEN);    //设置虚框模式

  dc.DrawFocusRect(&m_pre);



  CPen pen(PS_SOLID,3,RGB(255,0,0));

  dc.SelectObject(&pen);

  dc.SetROP2(R2_COPYPEN);  

  switch(m_nDrawType)

  {

  case 1:

    dc.SetPixel(point,RGB(255,0,0));

    break;

  case 2:

    dc.MoveTo(m_ptOrigin);

    dc.LineTo(point);

    break;

  case 3:

    dc.Rectangle(CRect(m_ptOrigin,point));

    break;

  case 4:

    dc.Ellipse(CRect(m_ptOrigin,point));

    break;

  }

  CView::OnLButtonUp(nFlags, point);



}



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

{

  // TODO: Add your message handler code here and/or call default

  if(m_bDraw)

  {

    CClientDC dc(this);

    dc.SetROP2(R2_XORPEN);    //设置虚框模式

    if (!m_pre.IsRectEmpty())

      dc.DrawFocusRect(&m_pre);

    m_new.right=point.x;  

    m_new.bottom=point.y;  

    if (!m_new.IsRectEmpty())

      dc.DrawFocusRect(&m_new);//画新矩形 

    m_pre.right=m_new.right;  

    m_pre.bottom=m_new.bottom; 

    dc.SetROP2(R2_WHITE);

  }    

  CView::OnMouseMove(nFlags, point);



}

    if(m_bDraw)

    {

    CClientDC dc(this);

    dc.SetROP2(R2_XORPEN);

    dc.DrawFocusRect(&m_pre);

    dc.SetROP2(R2_WHITE);

    }

CDC *pdc=this->GetDC();　　　//这里是pdc 等同于楼主的&dc

		CDC   MenDC;   

		CBitmap   bm;

		

		CRect rt;

		GetClientRect(&rt);

		MenDC.CreateCompatibleDC(pdc);   

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

		MenDC.SelectObject(&bm);

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

                //在这里使用MenDC来绘图，一定要是MenDC（内存ＤＣ）

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

		pdc->BitBlt(0,0,rt.Width(),rt.Height(),&MenDC,0,0,SRCCOPY);  

		MenDC.DeleteDC();   

		bm.DeleteObject();

		ReleaseDC(pdc);