PRB: OnTimer() Is Not Called Repeatedly for a List Control (200054)

MORE INFORMATION

The list control uses the timer for editing labels, and for scrolling. When you handle the timer message, if the timer ID is your own timer, don't call the default handler (CListCtrl::OnTimer).

In the sample code below, without the if clause in the CMyListCtrl::OnTimer function, the default WM_TIMER handler is always called, which destroys both the control's timer and your own timer. As a result, you should see a trace statement for each timer.

void CGensdiView::OnInitialUpdate() 
{
   CView::OnInitialUpdate();
	
   m_pCtrl = new CMyListCtrl;
   m_pCtrl->Create(WS_VISIBLE | WS_CHILD | WS_BORDER 
                   | LVS_REPORT | LVS_EDITLABELS, 
                   CRect(0, 0, 100, 150), this, 2134);

   m_pCtrl->InsertColumn(0, "one");
   m_pCtrl->InsertItem(0, "0 0 0 0 0 0 0 0 0 0 0");
   m_pCtrl->InsertItem(1, "1 1 1 1 1 1 1 1 1 1 1");
   m_pCtrl->InsertItem(2, "2 2 2 2 2 2 2 2 2 2 2");
}

void CGensdiView::OnLButtonDown(UINT nFlags, CPoint point) 
{
   m_pCtrl->m_timerID = m_pCtrl->SetTimer(14, 500, NULL);
   TRACE("timer %d is set\n", m_pCtrl->m_timerID);
}

CMyListCtrl::CMyListCtrl()
{
   m_timerID = -1;
}

void CMyListCtrl::OnTimer(UINT nIDEvent)
{
   if (nIDEvent != m_timerID)
      CListCtrl::OnTimer(nIDEvent);
   TRACE("OnTimer %d\n", nIDEvent);
}