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Problem with SendMessage/PostMessage

In my program I have a field where I can select some text in a editbox. That selection will then update some other fields  in my dialog.

To do that I have overloaded the editbox OnLButtonUp method, that method then posts a message to the parent dialog that recieves it and updates the proper fields...

It all works well in debug mode, but when I change to release mode it bombs out...

What is wrong with this?

Source for my OnLButtonUp function...

void CSmartCropEdit::OnLButtonUp(UINT nFlags, CPoint point)
{
    int start, end;
    CEdit::OnLButtonUp(nFlags, point);
    GetSel(start, end);
    if ((start != lastX) || (end != lastY)) {
        // Selection!
        GetParent()->PostMessage(WM_SMARTCHOPSELCHANGE);
        lastX = start;
        lastY = end;
    }
}

Messagehandler in the dialogbox...
void CCropRuleDlg::OnSmartCropSelChange()
{
   /* Yes, It is empty... But it doesn't matter
    * It crashes anyway...
    */
}

/Marre
0
marre111397
Asked:
marre111397
  • 4
1 Solution
 
lucidityCommented:
I find PostMessage cause me grief sometimes, try SendMessage instead, it should have the same effect.

As for OnSmartCropSelChange in the Dialog, I dunno.
0
 
plarocheCommented:
What does it do when it bombs out?
You can add debug info to your release build and you will be able to have a call stack and see the variables.
To achieve it add debug info in the C++ tab in the settings and ALSO in the link tab.
0
 
plarocheCommented:
Hell I just thought about it now, a good 20 mins after reading the question... must be friday! :-)

From your code it looks like your handler isn't declared correctly, make sure it is like this in your header file:

    afx_msg LONG OnAppMsg(WPARAM, LPARAM);

And in your implementation:

1: (message map)

    ON_MESSAGE(WM_USER_APPMSG, OnAppMsg)

2: (code)

LONG CMainFrame::OnAppMsg(WPARAM p1, LPARAM p2)
{
    CAppMsg *pAppMsg = (CAppMsg*)p1;
    m_pMsgMgr->NewMessage(pAppMsg);
    return 0;
}


This will fix your problem.
0
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plarocheCommented:
Why does this crash in release but not debug you say? Well it's because the MFC frameworks, when it calls message handlers via the message map, expects them to have a certain signature.  The call is then done by casting the function pointer to that expected signature. Since your doesn't match it crashes in release, a debug build is prevented from crashing.
0
 
marre111397Author Commented:
Thanks! An answer in less than 2h...

That really saved me a couple of hours... I tried to find an answer on dejanews, but I couldn't find any...
0
 
plarocheCommented:
I even answered in less than an hour! ;-)  Good luck...
0

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