Re: SaveBarState fails when it is called from a thread

From:
Faisal <faisalm83@gmail.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Wed, 9 Jul 2008 21:11:42 -0700 (PDT)
Message-ID:
<a22675c6-318f-4692-9873-e0c968f483eb@m36g2000hse.googlegroups.com>
On Jul 9, 6:43 pm, Joseph M. Newcomer <newco...@flounder.com> wrote:

The answer is simple: don't do that. It is not supported, and it won't work. You cannot
manipulate a window safely from a thread other than its owner, so it is no surprise when a
method that involves windows fails when invoked from some other thread. This is expected,
and you should not under any circumstances be manipulating any aspect of a window from a
secondary thread.
                                joe

On Wed, 9 Jul 2008 01:39:50 -0700 (PDT), Faisal <faisal...@gmail.com> wrote:

Hi,

In my application, I use SaveBarState() for persisting control bar
state.
The code fragment is something like this.

void CMainFrame::OnSavePersistance()
{
   SaveBarState(_T("My Persistence"));
      // Saves some information to an xml file
}

Since my xml saving takes some time I changed the code to execute in a
thread

UINT ThreadFn(LPVOID pParam)
{
   CMainFrame* pThis = (CMainFrame*)pParam;
   pThis->SaveBarState(_T("My Persistence"));

   return 0;
}

void CMainFrame::OnCntrlbartst()
{
   AfxBeginThread( ThreadFn, this );
}

But, now in the thread function SaveBarState() fails. It shows some
assertion in debug version. I think it is due to some mismatch in
MODULE_STATE.

statck trace for assert
CWnd::AssertValid() line 879 + 25 bytes
CControlBar::AssertValid() line 976
CStatusBar::AssertValid() line 732
AfxAssertValidObject(const CObject * 0x00431510 {CStatusBar
hWnd=0x00180c7e}, const char * 0x5f4ccfe8 THIS_FILE, int 531) line 108
CControlBar::GetBarInfo(CControlBarInfo * 0x00433d70) line 534
CFrameWnd::GetDockState(CDockState & {CDockState}) line 520
CFrameWnd::SaveBarState(const char * 0x0041844c `string') line 443
ThreadFn(void * 0x00431450) line 174

How can I avoid this problem.


Joseph M. Newcomer [MVP]
email: newco...@flounder.com
Web:http://www.flounder.com
MVP Tips:http://www.flounder.com/mvp_tips.htm


Hi,
is it possible to resolve this by changing MODULE_STATE or
THREAD_STATE
 to App's MODULE_STATE?
AfxSetModuleState( AfxGetAppModuleState() )

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