在文档视图中
我在OnDraw()中添加如下代码
    CBitmap bmp,*poldbmp;
    GetClientRect(&m_rectClient);
    CPen pen(PS_SOLID,1,RGB(255,0,0)),*pOld;
    CBrush bkbrush(RGB(255,255,0));
/*    CDC memDC;
    memDC.CreateCompatibleDC(pDC);
    membmp.CreateCompatibleBitmap(pDC,m_rectClient.Width(),m_rectClient.Height());
    poldbmp=(CBitmap *)memDC.SelectObject(&membmp);*/

    if(m_MemDC.GetSafeHdc()==NULL)
    {
        m_MemDC.CreateCompatibleDC(pDC);
        //
        //memDC->BitBlt(
        bmp.CreateCompatibleBitmap(pDC,m_rectClient.Width(),m_rectClient.Height());
        poldbmp=m_MemDC.SelectObject(&bmp);
        pOld=m_MemDC.SelectObject(&pen);
        m_MemDC.SetBkColor(RGB(0,0,0));
        //m_MemDC.MoveTo(450,400);
        //m_MemDC.LineTo(470,300);
        m_MemDC.FillRect(m_rectClient,&bkbrush);
        m_MemDC.BitBlt(0,0,m_rectClient.Width(),m_rectClient.Height(),&m_MemDC,10,0,SRCCOPY);
        pDC->BitBlt(0,0,m_rectClient.Width(),m_rectClient.Height(),&m_MemDC,0,0,SRCCOPY);
        bmp.DeleteObject();
        m_MemDC.SelectObject(poldbmp);
        m_MemDC.SelectObject(pOld );
        //memDC->DeleteDC();
        m_MemDC.DeleteDC();
    }

    else
    {
        m_MemDC.TextOut(100,100,"dfasdfsd");
        pDC->BitBlt(0,0,m_rectClient.Width(),m_rectClient.Height(),&m_MemDC,0,0,SRCCOPY);
    }

还添加个定时器，每一秒重画，怎么m_MemDC.TextOut();没有运行，没有显示出来。