Re: Fun with CStatic destructor

From:
"Tom Serface" <tserface@msn.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Thu, 17 Aug 2006 10:08:52 -0700
Message-ID:
<ezzsR$hwGHA.1772@TK2MSFTNGP06.phx.gbl>
Just a guess, but is there something in IssueLetter() or something it does
that could be causing the error after the fact? It's tough to trace the
source of an exception sometimes. What happens after that code?

Also, I notice you are setting a flag in the document to exit. Why not just
post a WM_CLOSE message or check the cancel return code from the dialog in
an else statement? Maybe there is someting that is not getting closed down
correctly because of the document getting closed or something like that.

Tom

"Paul S. Ganney" <paul.ganney@hey.nhs.uk> wrote in message
news:1155832107.931292.133380@75g2000cwc.googlegroups.com...

I'm getting very stumped here and wondered if anyone could help out.

The interesting bit of code is:
if(dlg.DoModal()==IDOK)
{
if(dlg.check[0].GetChecked())
IssueLetter('S',"SU","","",false,false,-1);
if(dlg.check[1].GetChecked())
IssueLetter('S',"SB","","",false,false,-1);
if(dlg.check[2].GetChecked())
IssueLetter('S',"SH","","",false,false,-1);
}

If I click OK on the dialog, the letters are produced by IssueLetter()
and all is well. If I click CANCEL then I get an unhandled exception in
this:
CCmdTarget::~CCmdTarget()
{
#ifndef _AFX_NO_OLE_SUPPORT
if (m_xDispatch.m_vtbl != 0)
((COleDispatchImpl*)&m_xDispatch)->Disconnect(); // HERE
ASSERT(m_dwRef <= 1);
#endif
#ifdef _AFXDLL
m_pModuleState = NULL;
#endif
}

Interestingly, the effects are the same when I comment out the if(dlg)s
in my code (i.e. leaving an empty if()). I get the same effect if I
don't check any checkboxes and select "OK" and if I do select one and
select "Cancel".

Looking at the callstack, the exception is occuring from a CStatic
destructor (the dialog is built on-the-fly so constructs it's own
statics and checkboxes), called during the dialog destructor called at
the end of the function the above code is in.

As I said at the top, I'm well stumped. To my mind, the static
destructors get called in exactly the same way whether I say "OK" or
"Cancel" but the evidence suggests otherwise.

I have overidden OnOK() and OnCancel() as follows, but can't see that
they should have any effect (and all work fine for other uses of this
dialog):

void CInputDlg::OnOK()
{
if(GetFocus()!=&m_ok) // came here by pressing RETURN
{
m_ok.SetFocus(); // m_ok is the OK button
m_ok.PostMessage(WM_LBUTTONDOWN);
}
else CDialog::OnOK();
}

void CInputDlg::OnCancel()
{
pDoc->SetExiting(true); // sets a flag in the document
CDialog::OnCancel();
}

I'm running VC6 with all the Service Packs, if that makes any
difference.

Any ideas?

Paul.

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