MFC: CToolTipCtrl causes ASSERT

Question

I have implemented tool tips seemingly successfully in an app which is MFC based and uses CPropertyPage. However after adding a button to open a dialog box called IDC_USERMSG which contains a single CEdit control on one of the CPropety pages an Assert is thrown when the IDC_USERMSG dialog is dismissed.

_AFXWIN_INLINE CWnd* CWnd::GetParent() const
{ 
    ASSERT(::IsWindow(m_hWnd)); // Asserts here.
    return CWnd::FromHandle(::GetParent(m_hWnd)); 
}

I belive this is because the IDC_USERMSG dialog no longer exsists at this stage because it has been closed.

Button/Tooltips implimented as follows.

BEGIN_MESSAGE_MAP(CUserData, CPropertyPage)
    // Displays dialog when button pressed    
    ON_BN_CLICKED(IDC_USERMSG, &CUserData::OnBnClickedUsermsgbtn)      
END_MESSAGE_MAP()

BOOL CUserData::OnInitDialog()    
{
    EnableToolTips(TRUE);
    static CString ToolTip;  
    CTTCtrl.Create(this); // CToolTipCtrl CTTCtrl is a global
    CTTCtrl.SetDelayTime(TTDT_AUTOPOP, 8000);
    CTTCtrl.SetMaxTipWidth(ToolTipWidth);

    ToolTip.LoadStringW(TT_REN);
    CTTCtrl.AddTool( GetDlgItem( IDC_TT_REN), ToolTip );

    return 0;
}   

BOOL CUserData::PreTranslateMessage(MSG* pMsg)
{
    CTTCtrl.RelayEvent( pMsg );
    CDialog::PreTranslateMessage(pMsg);

    // think I need some sort of filter here.

    return CDialog::PreTranslateMessage(pMsg);
}

Call Stack

mfc90ud.dll!CWnd::GetParent()  Line 297 + 0x2d bytes    C++
mfc90ud.dll!CWnd::FilterToolTipMessage(tagMSG * pMsg=0x00155570)  Line 392 + 0x8 bytes  C++
mfc90ud.dll!CWnd::_FilterToolTipMessage(tagMSG * pMsg=0x00155570, CWnd * pWnd=0x0012fa78)  Line 374 C++
mfc90ud.dll!CWnd::PreTranslateMessage(tagMSG * pMsg=0x00155570)  Line 1070  C++
mfc90ud.dll!CDialog::PreTranslateMessage(tagMSG * pMsg=0x00155570)  Line 56 + 0xc bytes C++
MyApp.exe!CUserData::PreTranslateMessage(tagMSG * pMsg=0x00155570)  Line 495    C++

Answer 1

You are calling CDialog::PreTranslateMessag twice, remove the second call.