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Is there anybody who can hunt Gozila?

leehdo
leehdo asked
on
Medium Priority
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Last Modified: 2013-11-20
Hello Experts...

I'm developing some application of which interface looks like Exproler.
Main frame splitted into two panes, TreeView and ListView, and in ListView when mouse moves on item, it shows up some information about item using tooltip.
You may see this interface in "Address Book" of Microsoft's Outlook Express.
"Address Book" shows each item's property using tooltip in this way.

So I coded my application and it looks work well in first time.

BUT, in a few minute I found some Gozila grade bug in my code, and it still lives happyly.

Would you like to hear my history and how this Gozila born?

In first time, I spent a lot of days for making item's information tooltip in multi-line. It does not simple as I think first.
So I asked my problem this page. Some kind experts helps me how it can be made. He suggested that I can find answers about multiline tooltip in the MSJ archives titled 'Tiptoe through the tooltips' on Visual Studio 5/6 CD or at their website at www.microsoft.com/msj.

In that archive I'm surely find answers and I think all my problem solved at that time.
But it did not work correctly in some condition.
See some part of my code below.
---------------------------------------------------------
BOOL CItemListView::PreTranslateMessage(MSG* pMsg)
{
   if(::IsWindow(m_ToolTip.m_hWnd) && pMsg->hwnd == m_hWnd)
   {
      switch(pMsg->message)
      {
         case WM_LBUTTONDOWN:    
         case WM_MOUSEMOVE:
         case WM_LBUTTONUP:    
         case WM_RBUTTONDOWN:
         case WM_MBUTTONDOWN:    
         case WM_RBUTTONUP:
         case WM_MBUTTONUP:
            m_ToolTip.RelayEvent(pMsg);
            break;
      }
   }

   return CListView::PreTranslateMessage(pMsg);
}

void CItemListView::OnMouseMove(UINT nFlags, CPoint point)
{
   const int nItemHit = m_pList->HitTest(point);

   if(nItemHit > -1)
   {
      if(nItemHit < 0 || nItemHit != m_nItemIndexHit)
      {
         // Use Activate() to hide the tooltip.
         m_ToolTip.Activate(FALSE);
      }

      if(nItemHit > -1)
      {
         m_ToolTip.Activate(TRUE);
         m_nItemIndexHit = nItemHit;
      }

   }

   CListView::OnMouseMove(nFlags, point);
}

BOOL CItemListView::OnToolTipNeedText(UINT id, NMHDR* pNMHDR, LRESULT* pResult)
{
   BOOL bHandledNotify = FALSE;
   CPoint CursorPos;
   VERIFY(::GetCursorPos(&CursorPos));
   m_pList->ScreenToClient(&CursorPos);

   CRect ClientRect;
   m_pList->GetClientRect(&ClientRect);
           
   // Make certain that the cursor is in the client rect, because the
   // mainframe also wants these messages to provide tooltips for the
   // toolbar.
   if(ClientRect.PtInRect(CursorPos))
   {
      TOOLTIPTEXT *pTTT = (TOOLTIPTEXT*)pNMHDR;
      m_nItemIndexHit = m_pList->HitTest(CursorPos);

      if(m_nItemIndexHit > -1)
      {
         // Adjust the text by filling in TOOLTIPTEXT
         CString strTip;
         strTip.Format("Item Num : %d\nSecond Line", m_nItemIndexHit);

         ASSERT(strTip.GetLength() < sizeof(pTTT->szText));
         ::strcpy(pTTT->szText, strTip);
      }
      else
          pTTT->szText[0] = 0;

               
      bHandledNotify = TRUE;
  }
           
  return bHandledNotify;
}
---------------------------------------------------------
I declared some variables like this and handled properly.

CToolTip m_ToolTip;
CListCtrl* m_pList;

As it is a part of my whole code, but continuing explanation.

When ListView is active, Tooltip work correct but I change active view to TreeView and moves mouse on ListView item it still shows up Tooltip, but it has wrong contents. Tooltip works correctly only when LisView is active view.
And more, when Tooltip works correctly some problem exist too.
Another Tooltip window, has same contents not multi line but one line long, is blinking behind my application window.

I have tried to find what is wrong and trace my code in debugger then I found some information.

In debugging mode, I ran my application and changed current view to TreeView using mouse click, and I moves mouse pointer on ListView's item. At this point I checked tooltip text's contents then I noticed that tooltip text is not wrong.
OnToolTipNeedText() function works well and HitTest() function works well too.
But before showing tooltip, OnToolTipNeedText() function called again and tooltip text became wrong.
I think that wrong coordinate problem causes this and calls m_ToolTip.Activate(FALSE); in OnMouseMove() function. And it is problem under MFC framework when showing tooltip. so I don't know and what is the difference in showing tooltip in split window.
If the answer really exist under MFC framework. it is out of my ablity.
So you Experts only can solve this problem.

I'm afraid my English is not good for you to understand what I want to say. I think it is better way for you to understand what I really I want to tell you is tracing my buggy code in debugging mode.
If you want I'll send simple project has this problem.

Let's hunt for Gozila with 300pts.
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Commented:
Send your sample code at plaroche@cybectec.com, I'll take a look at it.

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