Drawing a selection box using CRectTracker

From:

Anders Eriksson <andis59@gmail.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Sat, 26 May 2007 13:58:05 +0200

Message-ID:

<u9p5exj3wnmc.dlg@ostling.com>

Hello,

I have an MFC SDI CView application and I want to draw an selection box
when the user left clicks and move the mouse. I have found the CRectTracker
class but I can't get it to work

I have this code:

void CSCMLaserView2::OnLButtonDown(UINT nFlags, CPoint point)
{
        SetCapture();
        m_startPt = point;
        m_theRectTracker.TrackRubberBand(this,point,TRUE);
}

void CSCMLaserView2::OnLButtonUp(UINT nFlags, CPoint point)
{
    //Release the capture on the mouse
    ReleaseCapture();
    CSCMLaserDoc* pDoc = GetDocument();
    ASSERT(pDoc != NULL);
    CClientDC dc(this);
    OnPrepareDC(&dc);

    // Converts screen coordinates into logical ones
    dc.DPtoLP(&point);
  dc.DPtoLP(&m_startPt);
  // Select object

pDoc->SelectObjectByWindow((double)m_startPt.x/m_dViewScale,(double)m_startPt.y/m_dViewScale,(double)point.x/m_dViewScale,(double)point.y/m_dViewScale);
    Invalidate();
}

No box will be shown! If I remove the SetCapture/RelaseCapture I will get a
box but then the OnLButtonUp() will never be called...

Please Help!

// Anders
--
English is not my first, or second, language
so anything strange, or insulting, is due to
the translation.
Please correct me so I may improve my English!