mfc mdi添加背景图片

请在主窗口框架中加以下代码：

void CMainFrame::AdjustClientArea()
{
	// TODO: 在此添加专用代码和/或调用基类

	CMDIFrameWndEx::AdjustClientArea();
	if (m_wndClientArea.GetSafeHwnd() != NULL)
	{
	 	m_wndClientArea.Invalidate();
	}
}

BOOL CMainFrame::OnEraseMDIClientBackground(CDC* pDC) 
{ 
	
	if ((m_wndClientArea.GetSafeHwnd() != NULL)&& (pDC->GetSafeHdc()!=NULL))
	{	
		CDC menDc;
		HGDIOBJ pObj;
		CBitmap bitmap;
		bitmap.LoadBitmap(IDB_BITMAP2);
		BITMAP bmp;
		bitmap.GetBitmap(&bmp);

		menDc.CreateCompatibleDC(pDC);
		pObj = menDc.SelectObject(bitmap);
		CRect rect;
		m_wndClientArea.GetClientRect(&rect);
        pDC->SetStretchBltMode(COLORONCOLOR);
		pDC->StretchBlt(0, 0, rect.Width(), rect.Height(), &menDc, 0, 0, bmp.bmWidth, bmp.bmHeight, SRCCOPY);

		menDc.SelectObject(pObj);
		menDc.DeleteDC();
		return TRUE;
	}
	
	return FALSE;
}