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Handling TTN_NEEDTEXT Notification for Tool Tips

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|  Overview |  How Do I

As part of enabling tool tips, you handle the TTN_NEEDTEXT message by adding the following entry to your owner window’s message map:

ON_NOTIFY_EX(TTN_NEEDTEXT, 0**,memberFxn)**

memberFxn

The member function to be called when text is needed for this button.

Note that the ID of a tool tip is always 0.

Declare your handler function in the class definition as follows:

BOOL CMyClass**::memberFxn(UINTid,NMHDR** * pTTTStruct**,LRESULT*pResult);**

where the italicized parameters are:

  • id   Identifier of the control that sent the notification. Not used. The control id is taken from the NMHDR structure.

  • pTTTStruct   A pointer to the structure. This structure is also discussed further in The TOOLTIPTEXT Structure.

  • pResult   A pointer to result code you can set before you return. TTN_NEEDTEXT handlers can ignore the pResult parameter.

As an example of a form-view notification handler:

BOOL CMyFormView::OnToolTipNotify( UINT id, NMHDR * pNMHDR, LRESULT * pResult );
{
    TOOLTIPTEXT *pTTT = (TOOLTIPTEXT *)pNMHDR;
    UINT nID =pNMHDR->idFrom;
    if (pTTT->uFlags & TTF_IDISHWND)
    {
        // idFrom is actually the HWND of the tool
        nID = ::GetDlgCtrlID((HWND)nID);
        if(nID)
        {
            pTTT->lpszText = MAKEINTRESOURCE(nID);
            pTTT->hinst = AfxGetResourceHandle();
            return(TRUE);
        }
    }
    return(FALSE);
}
void CTestView::OnInitialUpdate()
{
    CMyFormView::OnInitialUpdate();
    EnableToolTips(TRUE);
}