mfc, Multiple Views: how to open both views at startup or on new document

by **Manuel M** » Sun, 10 Sep 2006 22:46:19 GMT

Following the CHKBOOK sample in MSDN I finally have two
different views associated with the same document, and working
simultaneously. The problem is that when I run my program I
only get the first view. The second view only appears when I
*open* a document from a file, and not when I start a new one.

The cause is no wonder, because the piece of code that opens
the second view is only inside the OpenDocumentFile() function.
That makes sense in the sample, which is designed to work always
on a file (either is opens an existing file, or it creates a new
one).

Q: What code should I add where, for my application to open both
views on a *new* document?

Furthermore, I have learnt that you can resize a view by calling
its parent frame's MoveWindow() function. I would like to size
each of my two views to a certain desired size at startup. What is
the appropriate place to add this code?

by **Joseph M. Newcomer** » Mon, 11 Sep 2006 09:44:11 GMT

In the OnNewDocument handler you could create the second view.
joe

Joseph M. Newcomer [MVP]
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by **Manuel M** » Mon, 11 Sep 2006 20:09:12 GMT

Thanks for your reply. I'm trying to do that, with this piece of code:

BOOL CSequDoc::OnNewDocument()
{
if (!CDocument::OnNewDocument())
return FALSE;
// (...)
InitDocument(); CMDIChildWnd* pNewFrame = (CMDIChildWnd*)
(CSequApp::m_pEditorTemplate->CreateNewFrame(pDoc, NULL));
if (pNewFrame == NULL)
return FALSE; // not created
ASSERT_KINDOF(CMDIChildWnd, pNewFrame);
CSequApp::m_pEditorTemplate->InitialUpdateFrame(pNewFrame, pDoc);
return TRUE;
}

The problem is that I don't know how to get the pointer to the
active document (pDoc). I've browsed through the member
functions of CDocument and CWinApp, and I can't find one
that gives me said pointer. How should I do that?

by **xrxst32** » Mon, 11 Sep 2006 20:47:47 GMT

Try "this" for this document.

by **Joseph M. Newcomer** » Mon, 11 Sep 2006 22:34:09 GMT

'this'. You're IN the document!
joe

Joseph M. Newcomer [MVP]
email: XXXX@XXXXX.COM
Web: http://www.flounder.com
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by **Manuel M** » Tue, 12 Sep 2006 00:19:02 GMT

Thank you guys! Now you see how much of a begginer I am.

But now I get a compiler error that looks very strange to me:
C:\(...)\SequDoc.cpp(79) : error C2227: left of '->CreateNewFrame' must
point to class/struct/union
C:\(...)\SequDoc.cpp(83) : error C2227: left of '->InitialUpdateFrame'
must point to class/struct/union

This is the code, with the troublesome lines marked:

BOOL CSequDoc::OnNewDocument()
{
if (!CDocument::OnNewDocument())
return FALSE;
InitDocument();
CMDIChildWnd* pNewFrame = (CMDIChildWnd*)
(CSequApp::m_pEditorTemplate->CreateNewFrame(this, NULL)); // <---
if (pNewFrame == NULL)
return FALSE; // not created
ASSERT_KINDOF(CMDIChildWnd, pNewFrame);
CSequApp::m_pEditorTemplate->InitialUpdateFrame(pNewFrame, this); //
<---

return TRUE;
}

Both pointers are of the correct type, CMultiDocTemplate*. And both
are declared as public in the application class and initialized in
CSequApp::InitInstance() (correctly, I assume, since otherwise
the program could not have worked before, when I wrote the first
post of this thread).

I have tried other ways, and it seems that it's illegal to access those
member variables in CSequApp. If I try to assign the value in this way:
CMultiDocTemplate* pEditorTemplate =
CSequApp::m_pEditorTemplate;
then I get "Illegal reference to data member
CSequApp::m_pEditorTemplate
in a static member function".

And it's no use defining a GetEditorTemplate() function in CSequApp,
because any calls to it seem to be illegal (still don't know why).
Those give me a "illegal call to non-static member function"
error.

It looks like it must be a big conceptual mistake on my side, is it?

by **Joseph M. Newcomer** » Tue, 12 Sep 2006 02:17:17 GMT

I would be disinclined to access the app in the CDocument class.

Now that I revisit the problem, I basically overrode CWinApp:OnFileNew and
CWinApp::OnFileOpen in my CWinApp class and created the secondary view there. It has the
advantage that the template is readily accessible and doesn't require any special magic to
get to it.

Note that CSequApp::m_pEditorTemplate is *not* accessing the member variable; this is
erroneous syntax. You would have to write
((CSequApp*)AfxGetApp())->m_pEditorTemplate;
but you should not be including the CWinApp class in the CDocument module (I know
Microsoft puts it there, but the first thing to do is to eliminate it)
joe

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

by **Manuel M** » Tue, 12 Sep 2006 03:11:58 GMT

Done, I've overridden OnFileNew, copy-pasting code from CHKBOOK. It
now works OK:

void CSequApp::OnFileNew()
{
CString strNewFileName;
strNewFileName = "untitled.sequ";

// If file doesn't already exist, then create it.
CFile file;
CFileStatus status;
if (!file.GetStatus(strNewFileName, status))
{
file.Close();
}

// Open the file now that it has been created.
OpenDocumentFile(strNewFileName);
}

The only thing I don't like now is that if I close any of the two
views,
I am promted to save the document, and then again when I close
the other view (if I didn't save it before). But it's not much trouble,
so I'll let it be for the moment.

Thank you very much for your time and effort,
Manuel Mats.

mfc, Multiple Views: how to open both views at startup or on new document

mfc >> Multiple Views: how to open both views at startup or on new document

mfc >> Multiple Views: how to open both views at startup or on new document

mfc >> Multiple Views: how to open both views at startup or on new document

Multiple Views: how to open both views at startup or on new document

Multiple Views: how to open both views at startup or on new document

Multiple Views: how to open both views at startup or on new document

Multiple Views: how to open both views at startup or on new document

Multiple Views: how to open both views at startup or on new document