MFC tooltips only show up on special occasions

Question

I have been tasked with assigning tooltips to each item in a configuration menu. I have completed "adding" the tooltip to each control on the page, but it seems sometimes the tooltip shows up and sometimes it does not, depending on the position of the control on the screen.

To tooltip-erize the pages I first

EnableToolTips(TRUE);

In each CPropertyPage's OnInitDialog method. I then add the notification map

ON_NOTIFY_EX(TTN_NEEDTEXT, 0, OnToolTipText)

With the function OnToolTipText looking as such

BOOL CCfgPrefPage::OnToolTipText( UINT id, NMHDR * pNMHDR, LRESULT * pResult )
{
    TOOLTIPTEXT *pTTT = (TOOLTIPTEXT *)pNMHDR;
    UINT nID = pNMHDR->idFrom;

    if (pTTT->uFlags & TTF_IDISHWND)
    {
        nID = ::GetDlgCtrlID((HWND)nID);
        if(nID)
        {
            if( nID == GetDlgItem(IDC_PICKDIST_EDIT)->GetDlgCtrlID())  
                _tcsncpy_s(pTTT->szText, _T("Tool Tip Text"), _TRUNCATE);
            else if( nID == GetDlgItem(IDC_ENDPTTOL_EDIT)->GetDlgCtrlID())  
                _tcsncpy_s(pTTT->szText, _T("Tool Tip Text"), _TRUNCATE);

            pTTT->lpszText = pTTT->szText; // Sanity Check
            pTTT->hinst = AfxGetResourceHandle(); // Don't think this is needed at all
            return TRUE;
        }
    }
    return FALSE;
}

It seems for some of my controls the tool tip will not show up. For most of the check box controls the tool tip displays, but for a few they just do not show. There are no other controls covering them up, they are not disabled.

Another thing, if I use the non-standard cursor windows repeatedly flashes the tool tip, so much so it is unreadable in some cases. How can I fix this? This is not a problem on CEdit controls, so why is it a problem elsewhere?

EDIT: Update, the controls that have been on the pages for years seem to show tool tips. Any control that I try to add now/today will not show tool tips at all. No matter the position, control type, settings, I cannot get a single tool tip to show on a newly inserted control.

Answer 1

Working with a toolbar which repeats some menu items from menus of an older MFC application, I have worked on this issue of tool tips as well as (1) modifying the toolbar bit map to include additional icons and (2) providing user feedback on current application state. My problem is that I have to do most of this by hand rather than using the various wizards and tools.

What I have done is to (1) add new members to the CView derived class to handle additional messages, (2) modified the toolbar bit map to add in the additional icons using both MS Paint and the Resource Editor, and (3) added new event ids and event handlers to the message map for the CView derived class.

One problem I ran into with the toolbar bitmap change was that since I was inserting an icon, I had to shift an existing icon in the bitmap to the right. My first attempt at this resulted in the shifted icon showing as a blank on the application toolbar. Then I realized that I needed to add a bit more to the length of the toolbar bitmap. After adding a couple more columns to the last icon in the toolbar bitmap to make it a standard width in pixels, the icon displayed properly.

For tooltips I added the following to the message map:

ON_NOTIFY_EX(TTN_NEEDTEXT, 0, OnToolTipText)

I then added the following method to my class to handle the notifications for my menu items. As a side note, it appears that OnToolTipText() is the standard method used in CFrameWnd class and CMDIChildWnd class however CView derives from CWnd as does CFrameWnd so I doubt it makes a difference as to what the method is named.

inline BOOL CPCSampleView::OnToolTipText( UINT id, NMHDR * pNMHDR, LRESULT * pResult )
{
    static wchar_t toolTextToggleExportSylk [64] = L"Toggle SYLK export.";
    static wchar_t toolTextClearWindow [64] = L"Clear the log displayed.";
    static wchar_t toolTextConnectLan [64] = L"Log on the POS terminal through the LAN.";

    TOOLTIPTEXT *pTTT = (TOOLTIPTEXT *)pNMHDR;

    switch (pNMHDR->idFrom) {
        case ID_TOGGLE_SYLK_EXPORT:
            pTTT->lpszText = toolTextToggleExportSylk;
            return TRUE;
        case ID_WINDOW_CLEAR:
            pTTT->lpszText = toolTextClearWindow;
            return TRUE;
        case ID_CONNECT_LAN_ON:
            pTTT->lpszText = toolTextConnectLan;
            return TRUE;
    }
    // if we do not handle the message then return FALSE to let someone else do it.
    return FALSE;
}

For the user feedback on a menu item which toggles a file export when doing reports I provided the following changes to the message map and then implemented the necessary methods. There are two types of messages involved so I had to add two methods and two new message map entries:

// New message map entries to handle the menu item selection event
// and to update the menu item and the toolbar icon with state changes
ON_COMMAND(ID_TOGGLE_SYLK_EXPORT, OnToggleExportSylk)
ON_UPDATE_COMMAND_UI(ID_TOGGLE_SYLK_EXPORT, OnUpdateToggleExportSylk)


// New methods added to the CView derived class

// handle the menu selection event generated by either selecting the menu item
// from the menu or by clicking on the icon in the toolbar.
void CPCSampleView::OnToggleExportSylk()
{
    // Exclusive Or to toggle the indicator bit from 0 to 1 and 1 to 0.
    GetDocument()->ulReportOptionsMap ^= CPCSampleDoc::ulReportOptionsExportSylk;
}

// handle the request from the MFC framework to update the displayed state this
// not only does a check mark against the menu item it also causes the toolbar
// icon to appear depressed if click is set or non-depressed if click is not set
inline void CPCSampleView::OnUpdateToggleExportSylk (CCmdUI* pCmdUI) 
{
    if (GetDocument()->ulReportOptionsMap & CPCSampleDoc::ulReportOptionsExportSylk)
    {
        // SYLK export is turned on so indicate status to the user. This will
        // put a check mark beside the menu item and show the toolbar button depressed
        pCmdUI->SetCheck (1);
    }
    else
    {
        // SYLK export is turned off so indicate status to the user.  This will
        // remove the check mark beside the menu item and show the toolbar button as raised.
        pCmdUI->SetCheck (0);
    }
}

The resource file changes were needed to provide a new button for the toggle action as well as to add a new menu item for the toggle action. I am using the same resource id for several different things since these are all separate. So the id for the resource string is the same as for the menu item and is same for the toolbar button so as to simplify my life and make it easy to find all the particular bits and pieces.

The toolbar resource file definition looks like:

IDR_MAINFRAME TOOLBAR  16, 15
BEGIN
    BUTTON      ID_CONNECT_LAN_ON
    SEPARATOR
    BUTTON      ID_WINDOW_CLEAR
    SEPARATOR
    BUTTON      ID_TOGGLE_SYLK_EXPORT
    SEPARATOR
    BUTTON      ID_APP_ABOUT
END

And the specific part of the menu, which uses the same resource id for the toggle event id looks like:

MENUITEM "Export to SYLK file",         ID_TOGGLE_SYLK_EXPORT

Then to provide the status bar text which shows up with a mouse over there is a string table addition:

ID_TOGGLE_SYLK_EXPORT   "Toggle export of SYLK format report files for spreadsheets."

The lpszText member of the struct is describe in the MSDN documentation for the TOOLINFO struct as:

Pointer to the buffer that contains the text for the tool, or identifier of the string resource that contains the text. This member is sometimes used to return values. If you need to examine the returned value, must point to a valid buffer of sufficient size. Otherwise, it can be set to NULL. If lpszText is set to LPSTR_TEXTCALLBACK, the control sends the TTN_GETDISPINFO notification code to the owner window to retrieve the text.

Reviewing the existing answer to this question, I wondered about the if statement check for the TTF_IDISHWND flag. The MSDN documentation for the TOOLINFO struct has this to say:

Indicates that the uId member is the window handle to the tool. If this flag is not set, uId is the tool's identifier.

Answer 2

If you do not want to use helper class I have proposed then fix the problems in your code. First, use ON_NOTIFY_EX_RANGE macro when mapping the even handler, like this (this will cover all IDs):

ON_NOTIFY_EX_RANGE(TTN_NEEDTEXTA, 0, 0xFFFF, OnToolTipText)

Next, you need to fix your function. I see a few problems here. First, when testing for TTF_IDISHWND flag you only need to re-initalise the nID. You do not need to apply this to the whole function. Second, after all manipulations, your nID will be the actual dialog ID. There is no need to GetDlgItem() function

BOOL CCfgPrefPage::OnToolTipText( UINT id, NMHDR * pNMHDR, LRESULT * pResult )
{
    TOOLTIPTEXT *pTTT = (TOOLTIPTEXT *)pNMHDR;
    UINT nID = pNMHDR->idFrom;

    if (pTTT->uFlags & TTF_IDISHWND)
    {
        nID = ::GetDlgCtrlID((HWND)nID);
    }
    if(nID)
    {
        if( nID == IDC_PICKDIST_EDIT)  
            _tcsncpy_s(pTTT->szText, _T("Tool Tip Text"), _TRUNCATE);
        else if( nID == IDC_ENDPTTOL_EDIT)  
            _tcsncpy_s(pTTT->szText, _T("Tool Tip Text"), _TRUNCATE);

        //pTTT->lpszText = pTTT->szText; // Sanity Check
        *pResult = 0;
        return TRUE;
    }
    return FALSE;
}