SVDI: a "Single View, Multiple Documents" MFC Architecture

// docmulti2.cpp : implementation of the CSingleViewMultiDocTemplate class
//
#include "stdafx.h"
#include "docmulti2.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

// registered message for view creation
UINT _afxMsgCreateView = RegisterWindowMessage(_T("WM_CREATEVIEW"));
// registered message for view update
UINT _afxMsgUpdateView = RegisterWindowMessage(_T("WM_UPDATEVIEW"));


// CSingleViewMultiDocTemplate

CSingleViewMultiDocTemplate::CSingleViewMultiDocTemplate(UINT nIDResource, CRuntimeClass* pDocClass,
		CRuntimeClass* pFrameClass, CRuntimeClass* pViewClass)
		: CMultiDocTemplate(nIDResource, pDocClass,
		pFrameClass, pViewClass)
{
}

/////////////////////////////////////////////////////////////////////////////
// CSingleViewMultiDocTemplate commands

CDocument* CSingleViewMultiDocTemplate::OpenDocumentFile(LPCTSTR lpszPathName,
	BOOL bMakeVisible)
{
	BOOL bCreated = FALSE;      // => view created

	// Document creation
	CDocument* pDocument = CreateNewDocument();
	if (pDocument == NULL)
	{
		TRACE(traceAppMsg, 0, "CDocTemplate::CreateNewDocument returned NULL.\n");
		AfxMessageBox(AFX_IDP_FAILED_TO_CREATE_DOC);
		return NULL;
	}
	ASSERT_VALID(pDocument);

	// Looking for main frame
	CFrameWnd* pFrame = (CFrameWnd*)AfxGetMainWnd();
	if (pFrame == NULL)
	{
		AfxMessageBox(AFX_IDP_FAILED_TO_CREATE_DOC);
		delete pDocument;       // explicit delete on error
		return NULL;
	}
	ASSERT_KINDOF(CFrameWnd, pFrame);
	ASSERT_VALID(pFrame);

	// Looking for a view
	CView* pView = (CView*)pFrame->GetDescendantWindow(AFX_IDW_PANE_FIRST, TRUE);

	// Is it a view ?
	if ((pView != NULL) && !pView->IsKindOf(RUNTIME_CLASS(CView)))
		pView = NULL;

	if (pView == NULL)
	{
		// View does not exist, creating it
		pView = CreateNewView(pDocument, pFrame);
		if (!pView)
		{
			AfxMessageBox(AFX_IDP_FAILED_TO_CREATE_DOC);
			delete pDocument;       // explicit delete on error
			return NULL;
		}
		bCreated = TRUE;

		// make sure the child windows have been properly sized
		pFrame->RecalcLayout();
	}
	else
	{
		// Somme views exist, connect them to new document
		CDocument* pPrevDocument = pView->GetDocument();
		ASSERT(pPrevDocument != NULL);
		POSITION pos = pPrevDocument->GetFirstViewPosition();
		while (pos != NULL) {
			pView = pPrevDocument->GetNextView(pos);
			pPrevDocument->RemoveView(pView);
			pDocument->AddView(pView);
		}
	}

	if (lpszPathName == NULL)
	{
		// create a new document - with default document name
		SetDefaultTitle(pDocument);

		// avoid creating temporary compound file when starting up invisible
		if (!bMakeVisible)
			pDocument->m_bEmbedded = TRUE;

		if (!pDocument->OnNewDocument())
		{
			// user has be alerted to what failed in OnNewDocument
			TRACE(traceAppMsg, 0, "CDocument::OnNewDocument returned FALSE.\n");
			if (bCreated) {
				// Special case of splitter window
				CSplitterWnd* pSplitter = CView::GetParentSplitter(pView, TRUE);
				if (pSplitter != NULL)
					pSplitter->DestroyWindow();
				else
					pView->DestroyWindow();
			}
			delete pDocument;       // explicit delete on error
			return NULL;
		}

		// it worked, now bump untitled count
		m_nUntitledCount++;
	}
	else
	{
		// open an existing document
		CWaitCursor wait;
		if (!pDocument->OnOpenDocument(lpszPathName))
		{
			// user has be alerted to what failed in OnOpenDocument
			TRACE(traceAppMsg, 0, "CDocument::OnOpenDocument returned FALSE.\n");
			if (bCreated) {
				// Special case of splitter window
				CSplitterWnd* pSplitter = CView::GetParentSplitter(pView, TRUE);
				if (pSplitter != NULL)
					pSplitter->DestroyWindow();
				else
					pView->DestroyWindow();
			}
			delete pDocument;       // explicit delete on error
			return NULL;
		}
		pDocument->SetPathName(lpszPathName);
	}

	InitialUpdateFrame(pFrame, pDocument, bMakeVisible);
	return pDocument;
}

CView* CSingleViewMultiDocTemplate::CreateNewView(CDocument* pDoc, CFrameWnd* pFrame)
{
	if (NULL != pDoc)
		ASSERT_VALID(pDoc);
	ASSERT(pFrame != NULL);

	// create a view wired to the specified document
	CCreateContext context;
	context.m_pCurrentFrame = pFrame;
	context.m_pCurrentDoc = pDoc;
	context.m_pNewViewClass = m_pViewClass;
	context.m_pNewDocTemplate = this;

	// The frame must process this message
	pFrame->SendMessage(_afxMsgCreateView, (WPARAM)&context);

	return (CView*)pFrame->GetDescendantWindow(AFX_IDW_PANE_FIRST, TRUE);
}


IMPLEMENT_DYNAMIC(CSingleViewMultiDocTemplate, CMultiDocTemplate)