重载了窗口OnEraseBkgnd设置背景图, 导致窗口里Slider控件背景全变黑,求助!

Question

郁闷啊!怎么回事啊?

Answer 1

BOOL CMyDlg::OnEraseBkgnd(CDC* pDC)    
{   
    CDC dc;   
    dc.CreateCompatibleDC(pDC);   
    CBitmap *pOldBit=dc.SelectObject(&m_Back);  
        BITMAP hb;   
    m_Back.GetBitmap(&hb);   
  
    CRect rt;   
    GetClientRect(&rt);   
       
    pDC->StretchBlt(0, 0, rt.Width(), rt.Height(),   
        &dc, 0, 0, hb.bmWidth, hb.bmHeight, SRCCOPY);  //dc.SelectObject (pOldBit);//
  
    return TRUE;   
}   

Answer 2

BOOL CMyDlg::OnEraseBkgnd( CDC* pDC )
{
RECT rt;   
GetWindowRect(&rt);   
ScreenToClient(&rt);
pDC->FillSolidRect(&rt, RGB(0,255,0));
return TRUE;
}

Answer 3

给你一段代码：
if( m_bmpBackground.GetSafeHandle() != NULL )
    {
        CDC*   pDCTemp = new CDC;;
        BITMAP bmp;        pDCTemp->CreateCompatibleDC( &dc );        m_bmpBackground.GetBitmap( &bmp );        // Select the bitmap into the temp device context
        CBitmap* pOldBitmap = (CBitmap*) pDCTemp->SelectObject( &m_bmpBackground );        // Stretch the bitmap to fill the entire control area
        pDCMem->StretchBlt( 0, 0, rFrame.Width(), rFrame.Height(), pDCTemp,
                            0, 0, bmp.bmWidth, bmp.bmHeight, SRCCOPY);        pDCTemp->SelectObject( pOldBitmap ); 
        
        delete pDCTemp;
    }
    else

Answer 4

最好是在OnPaint中绘制, 因为WM_PAINT消息在WM_ERASEBACKGROND之后响应。