Can't display Tool Tips in VC++6.0
- by Paul
I'm missing something fundamental, and probably both simple and obvious.
My issue:
I have a view (CPlaybackView, derived from CView).
The view displays a bunch of objects derived from CRectTracker (CMpRectTracker).
These objects each contain a floating point member.
I want to display that floating point member when the mouse hovers over the CMpRectTracker.
The handler method is never executed, although I can trace through OnIntitialUpdate, PreTranslateMessage,
and OnMouseMove.
This is in Visual C++ v. 6.0.
Here's what I've done to try to accomplish this:
1. In the view's header file:
public:
BOOL OnToolTipNeedText(UINT id, NMHDR * pNMHDR, LRESULT * pResult);
private:
CToolTipCtrl m_ToolTip;
CMpRectTracker *m_pCurrentRectTracker;//Derived from CRectTracker
2. In the view's implementation file:
a. In Message Map:
ON_NOTIFY_EX(TTN_NEEDTEXT,0,OnToolTipNeedText)
b. In CPlaybackView::OnInitialUpdate:
if (m_ToolTip.Create(this, TTS_ALWAYSTIP) && m_ToolTip.AddTool(this))
{
m_ToolTip.SendMessage(TTM_SETMAXTIPWIDTH, 0, SHRT_MAX);
m_ToolTip.SendMessage(TTM_SETDELAYTIME, TTDT_AUTOPOP, SHRT_MAX);
m_ToolTip.SendMessage(TTM_SETDELAYTIME, TTDT_INITIAL, 200);
m_ToolTip.SendMessage(TTM_SETDELAYTIME, TTDT_RESHOW, 200);
}
else
{
TRACE("Error in creating ToolTip");
}
this->EnableToolTips();
c. In CPlaybackView::OnMouseMove:
if (::IsWindow(m_ToolTip.m_hWnd))
{
m_pCurrentRectTracker = NULL;
m_ToolTip.Activate(FALSE);
if(m_rtMilepostRect.HitTest(point) >= 0)
{
POSITION pos = pDoc->m_rtMilepostList.GetHeadPosition();
while(pos)
{
CMpRectTracker tracker = pDoc->m_rtMilepostList.GetNext(pos);
if(tracker.HitTest(point) >= 0)
{
m_pCurrentRectTracker = &tracker;
m_ToolTip.Activate(TRUE);
break;
}
}
}
}
d. In CPlaybackView::PreTranslateMessage:
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;
}
}
e. Finally, the handler method:
BOOL CPlaybackView::OnToolTipNeedText(UINT id, NMHDR * pNMHDR, LRESULT * pResult)
{
BOOL bHandledNotify = FALSE;
CPoint CursorPos;
VERIFY(::GetCursorPos(&CursorPos));
ScreenToClient(&CursorPos);
CRect ClientRect;
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;
CString str;
str.Format("%f", m_pCurrentRectTracker->GetMilepost());
ASSERT(str.GetLength() < sizeof(pTTT->szText));
::strcpy(pTTT->szText, str);
bHandledNotify = TRUE;
}
return bHandledNotify;
}
