Re: timer-event in a CDocument-derived class
On 19 Aug., 20:22, Joseph M. Newcomer <newco...@flounder.com> wrote:
See by essay on how to add a timer to a CDocument class, on my MVP Tips s=
ite.
Hint: it involves creating a dummy window to handle the timer notificatio=
n.
joe
More below...
On Thu, 19 Aug 2010 08:37:44 -0700 (PDT), mfc <mfcp...@googlemail.com> wr=
ote:
Hi,
using a SDI (single-doc-template) application, is it also possible to
generate a timer-event in a CDocument-derived class (http://
www.flounder.com/cdocumenttimer.htm)?
My default document class is:
class CMIAppDoc : public CDocument
For my serial-ports, I need a timer. Therefore I tried to implement a
second class ( CTimedDocument) derived from the CDocument. Do I have
to derived this class from my CMIAppDoc (because of the sdi
restriction to only one document)?
class CSerialWrite : public CWinThread
{
CTimedDocument tdoc;
CTimerWnd wnd;
void Init(void);
};
void CSerialWrite::Init(void)
{
wnd.Start(3000, &tdoc);
}
The problem I have is that the virtual method
virtual void OnTimer(){ ASSERT(FALSE); }
failed, because it is not correct declared in my subclass?!?
class CTimedDocument : public CDocument
{
protected:
virtual void OnTimer(){ ASSERT(FALSE); }
};
class CSerialTimeDoc : public CTimedDocument
{
protected:
virtual void OnTimer();
****
Note that you cannot put an OnTimer handler in a CDocument class. This=
is because
WM_TIMER messages are only sent to windows, and a document cannot receive=
them.
You cannot override this method. For one thing, if you read the docume=
ntation of OnTimer,
you would have seen it is
afx_msg void OnTimer(UINT_PTR nIdEvent)
which means that (a) it is member of CWnd, and therefore cannot be in CDo=
cument (b) it is
not virtual, so your declaration of a virtual method is meaningless.
I note that the most critical piece of code, the piece of code where you =
set the timer,
has not been shown, so it is not clear how we are supposed to guess at wh=
at you did, or
why you would expect the OnTimer method to be called.
joe
****>};
best regards
Hans
Joseph M. Newcomer [MVP]
email: newco...@flounder.com
Web:http://www.flounder.com
MVP Tips:http://www.flounder.com/mvp_tips.htm- Zitierten Text ausblenden =
-
- Zitierten Text anzeigen -
thanks for your answer. I`m using your CTimerWnd class. In my thread-
class I call the CTimerWnd::Start() method. -> afx_msg OnTimer is
called and doc->OnTimer will take a look if there`s such an method in
the document subclass CSerialTimeDoc because doc is a member of
CTimedDocument. And CTimedDocument has only a virtual void OnTimer()
installed.
class CTimedDocument : public CDocument
{
protected:
virtual void OnTimer(){ ASSERT(FALSE); }
};
But I always get the ASSERT.
class CSerialTimeDoc : public CTimedDocument
{
protected:
virtual void OnTimer();
};
Here`s the start where I create the new window.
BOOL CTimerWnd::Start(UINT ms, CTimedDocument * d)
{
interval = ms;
doc = d;
return CWnd::Create(NULL, // class name, left MFC invent one
NULL, // title, meaningless
WS_CHILD, // child window
// conspicuous by its absense:
// WS_VISIBLE
CRect(0,0,10,10), // useless nonempty rectangle
AfxGetMainWnd(), // attach to main window, need someplace
IDC_STATIC); // window ID
}
void CTimerWnd::OnTimer(UINT nIDEvent)
{
if(doc != NULL)
doc->OnTimer(); //?!?!? virtual void
OnTimer(void) failed
CWnd::OnTimer(nIDEvent);
}
int CTimerWnd::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
if (CWnd::OnCreate(lpCreateStruct) == -1)
return -1;
SetTimer(IDT_TIMER, interval, NULL);
return 0;
}
best regards
Hans