Re: CFileDialog::DoModal() never returns

From:
Mikel <mikel.luri@gmail.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Thu, 21 Feb 2008 01:31:08 -0800 (PST)
Message-ID:
<f35519a0-8036-4282-a178-6e2d3779baea@t66g2000hsf.googlegroups.com>
See below:

On 21 feb, 09:27, jbreher <jbre...@discussions.microsoft.com> wrote:

I am encountering a wierd error, and I can't figure out which way to turn.=

Something deep within the call tree of CFileDialog::DoModal() is (apparent=

ly)

failing, causing the dialog to never be displayed, and the f() never to
return. Here's the failing code:


*************
Well, DoModal returns when you select a file o close the dialog, so if
the dialog is never displayed, it's logical that it doesn't return.
*************

void CPvtDlg::OnBnClickedBnFileBd()
{

    // specify a file
    CFileDialog fileOpenBox ( TRUE, =

                       

// BOOL bOpenFileDialog
                                NULL, =

                                   

// LPCTSTR lpszDefExt
                                NULL, =

                                   

// LPCTSTR lpszFileName
                                (OFN_HIDER=

EADONLY | OFN_OVERWRITEPROMPT),

// DWORD dwFlags
                                NULL, =

                                      =
                                  // LPCTS=
TR lpszFilter

                                NULL ); =

                                   

// CWnd* pParentWnd


************
You are using the defaults here, so why not remove them and use just
CFileDialog fileOpenBox(TRUE); ?
************

    // extract file name
    if( IDOK == fileOpenBox.DoModal() )
    {
        m_strFileNameBd = fileOpenBox.GetFileName();
        m_strPathNameBd = fileOpenBox.GetPathName();
    }
...

Single stepping, I am unable to step over the DoModal() call. Stepping int=

o

the call to DoModal(), I find myself inside dlgfile.cpp:

INT_PTR CFileDialog::DoModal()
{
        ASSERT_VALID(this);
        ASSERT(m_ofn.Flags & OFN_ENABLEHOOK);
        ASSERT(m_ofn.lpfnHook != NULL); // can still be a user h=

ook

        // zero out the file buffer for consistent parsing later
        ASSERT(AfxIsValidAddress(m_ofn.lpstrFile, m_ofn.nMaxFile))=

;

        DWORD nOffset = lstrlen(m_ofn.lpstrFile)+1;
        ASSERT(nOffset <= m_ofn.nMaxFile);
        memset(m_ofn.lpstrFile+nOffset, 0, (m_ofn.nMaxFile-nOffset=

)*sizeof(TCHAR));

        // This is a special case for the file open/save dialog=

,

        // which sometimes pumps while it is coming up but befo=

re it has

        // disabled the main window.
        HWND hWndFocus = ::GetFocus();
        BOOL bEnableParent = FALSE;
        m_ofn.hwndOwner = PreModal();
        AfxUnhookWindowCreate();
        if (m_ofn.hwndOwner != NULL && ::IsWindowEnabled(m_ofn.h=

wndOwner))

        {
                bEnableParent = TRUE;
                ::EnableWindow(m_ofn.hwndOwner, FALSE);
        }

        _AFX_THREAD_STATE* pThreadState = AfxGetThreadState();
        ASSERT(pThreadState->m_pAlternateWndInit == NULL);

        if (m_ofn.Flags & OFN_EXPLORER)
                pThreadState->m_pAlternateWndInit = this=

;

        else
                AfxHookWindowCreate(this);

        INT_PTR nResult;
        if (m_bOpenFileDialog)
                nResult = ::AfxCtxGetOpenFileName(&m_ofn=

);

        else
                nResult = ::AfxCtxGetSaveFileName(&m_ofn=

);

...
I am unable to step over the call to ::AfxCtxGetOpenFileName(&m_ofn); in t=

he

if branch above. Stepping into it allows me to step through

OPENFILENAME& CFileDialog::GetOFN()
{
        return *m_pOFN;

}

and

COMMDLG_AFXCTXFUNC(BOOL,GetOpenFileNameW,(LPOPENFILENAMEW
unnamed1),(unnamed1))

to

AFX_MODULE_STATE* AFXAPI AfxGetModuleState()
{
        _AFX_THREAD_STATE* pState = _afxThreadState;
        ENSURE(pState);
        AFX_MODULE_STATE* pResult;
        if (pState->m_pModuleState != NULL)
        {
                // thread state's module state serves as o=

verride

                pResult = pState->m_pModuleState;
        }
        else
        {
                // otherwise, use global app state
                pResult = _afxBaseModuleState.GetData();=

        }
        ENSURE(pResult != NULL);
        return pResult;

}

back through

COMMDLG_AFXCTXFUNC(BOOL,GetOpenFileNameW,(LPOPENFILENAMEW
unnamed1),(unnamed1))

I could probably continue, but it seems to me that I am inside the innards=

of an area of the libs that I have no business in. What is it up in the AP=

I

level that I am screwing up?


*******
I have tried stepping into all of the functions until it finally
displays the dialog, so I really don't know what is going wrong. Those
are MFC/WIN32 internals and I am not an expert on that...

Have you checked wether the dialog is under other windows, or outside
the screen? It shouldn't, but anyway.

Another thing that comes to mind, try setting breakpoints in all the
functions in CFileDialog and see where it stops...

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