Help with CToolTipCtrl callbacks

Glen Okita -- go@svpal.org
Wednesday, May 01, 1996

Environment: Win95, SC++ 7.2, MFC 3.2

I'm trying to use a CToolTipCtrl with some controls.  The problem is
that I'm not getting notification messages for callback tool tips.
The non-callback tool tips work just fine.

I've duplicated my problem with a (relatively) simple test case described 
below.  I know this message is a little long -- but I hope to err on the 
side of completeness and avoid confusion.

1. I create a default SDI app with the AppExpress (the wizard-equivalent).

2. I create a simple derived button class that forwards mouse messages
   to the tool tip RelayEvent():
      class CTTButton : public CButton
      {
      public:
          static CToolTipCtrl* sm_pTT;
      protected:
          virtual BOOL PreTranslateMessage( MSG* pMsg);
      };
      
      BOOL CTTButton::PreTranslateMessage( MSG* pMsg)
      {
          BOOL rv = CButton::PreTranslateMessage( pMsg);
          // Forward any mouse messages.
          if ( ! rv
              && pMsg->message >= WM_MOUSEFIRST
              && pMsg->message <= WM_MOUSELAST)
                  sm_pTT->RelayEvent( pMsg);
          return rv;
      }

3. In my view's OnCreate() I create a couple of test buttons and the
   tool tip control:
      int CttView::OnCreate(LPCREATESTRUCT lpCreateStruct)
      {
          if (CView::OnCreate(lpCreateStruct) == -1)
              return -1;
      
          // to do: Add your specialized creation code here
      
          m_btnTT.Create( "Ordinary", BS_PUSHBUTTON | WS_VISIBLE, CRect(2, 2, 80, 26), this, 600);
          m_btnTTCallback.Create( "Callback", BS_PUSHBUTTON | WS_VISIBLE, CRect(2, 28, 80, 52), this, 601);
      
          m_toolTip.Create( this);
          m_toolTip.AddTool( &m_btnTT, "Ordinary Tip");
          m_toolTip.AddTool( &m_btnTTCallback, LPSTR_TEXTCALLBACK);
      
          CTTButton::sm_pTT = &m_toolTip;
          
          return 0;
      }

4. The view also has a PreTranslate override to forward mouse messages
   to the tool tip control.

5. The view has a message map entry:
      ON_MESSAGE(WM_NOTIFY,OnNotify)

   And the message handler looks like:
      LONG CttView::OnNotify( UINT wParam, LONG lParam)
      {
          TOOLTIPTEXT* pTTT = (TOOLTIPTEXT*) lParam;
          if ( pTTT->hdr.code == TTN_NEEDTEXT)
          {
              TRACE1( " view notify %x\n", pTTT->hdr.idFrom);
              pTTT->hinst = NULL;
              pTTT->lpszText = "Callback Tip";
          }
          return TRUE;
      }

6. The message handler never gets called.  I've tried other variations
   like putting the message map on the frame and on the derived button,
   adding an OnChildNotify(), and looking for WM_NOTIFY in the
   PreTranslate override.
      From documentation and looking at MFC code, it seems to me that
   the view should be the window that receives the notification.

Would appreciate any explanation of what I'm missing, or perhaps a
snippet/sample of working code.  None of the MFC examples that come
with the compiler use a CToolTipCtrl.
                                                               Glen Okita
ti desrever sediT -- Tides reversed it                         go@svpal.org

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Glen Okita -- go@svpal.org
Friday, May 10, 1996

I submitted the following query:

>Environment: Win95, SC++ 7.2, MFC 3.2
>
>I'm trying to use a CToolTipCtrl with some controls.  The problem is
>that I'm not getting notification messages for callback tool tips.
>The non-callback tool tips work just fine.
> ... rest deleted for brevity...

The solution is to override the the virtual function:
   OnNotify(WPARAM wParam, LPARAM lParam, LRESULT* pResult)
   (the base class OnNotify is also called).

I was trying to handle the WM_NOTIFY message in a message map and
it don't work that way...
                                                               Glen Okita
ti desrever sediT -- Tides reversed it                         go@svpal.org

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