Re: Switch persistent views in MDI app

Vincent RICHOMME <>
Fri, 28 Apr 2006 21:19:24 +0200
This one :

And I have tried your suggestion it seems to work....
Your are a genious !!


AliR wrote:

Which line in SwitchToView is it breaking on?

Have you tried adding the new view first before removing the old view?


"Vincent RICHOMME" <> wrote in message


I am trying to switch between views in a MDI app but I can't.
I found some examples but I am not satisfied with them because they put
it in CDocument. To me it should be in CWinApp or even better in
CmainFrame for a SDI and ChildFrame for a MDI.
Anyway here is the code I use for my MDI app, but the line
pDoc->AddView(pNewView); in the SwitchToView gives me an exception with
the following line from debugger:

if (!AfxIsValidAddress(pOb, pOb->GetRuntimeClass()->m_nObjectSize, FALSE))
__vfptr 0xfeeefeee

I don't understand, all my views are declare DYNAMIC, ...

Does someone has a clean SwitchToView implementation, I am not
interested by code using CDocument like the ones found on CodeGuru or

// Our different Views
enum EViews

BOOL CMyApp::InitInstance()
 // Init all our views
  return TRUE;

void CMyApp::InitViews()
m_nCurView = 0; // Save index of the currently active view class

CMDIFrameWnd* pMainWnd = (CMDIFrameWnd*) AfxGetMainWnd();
CMDIChildWnd* pChild = (CMDIChildWnd*) pMainWnd->MDIGetActive();

   CView* pActiveView = pChild->GetActiveView();

    m_pViews[0] = pActiveView;
    m_pViews[1] = (CView*) new CSmartTokenTesterView;

    CDocument* pCurrentDoc = pChild->GetActiveDocument();
      CRect rect(0, 0, 0, 0); // gets resized later

    // Need to cast pointers to have correct Create functions called
    // CForm2 is CFormView::Create
for ( int nView=1; nView < N_VIEWS; nView++ )
m_pViews[nView]->Create(NULL, NULL, AFX_WS_DEFAULT_VIEW, rect,
          pChild, AFX_IDW_PANE_FIRST + 1, NULL);


CView* CMyApp::SwitchToView( UINT nIndex )
    ASSERT( nIndex >=0 && nIndex < N_VIEWS );

    CMDIFrameWnd* pMainWnd = (CMDIFrameWnd*) AfxGetMainWnd();
CMDIChildWnd* pChild = (CMDIChildWnd*) pMainWnd->MDIGetActive();
CView* pActiveView = pChild->GetActiveView();
CDocument* pDoc = pChild->GetActiveDocument();

if ( !pActiveView ) // No currently active view
        return NULL;

CView* pNewView = m_pViews[ nIndex ];

    if ( pNewView == pActiveView ) // Already there
        return pActiveView;

// Set flag so that document will not be deleted when view is dettached.
BOOL bAutoDelete = m_bAutoDelete;
m_bAutoDelete = FALSE;
// Dettach existing view
// restore flag
m_bAutoDelete = bAutoDelete;

    m_nCurView = nIndex; // Store the new current view's index

    // exchange view window ID's so RecalcLayout() works
UINT temp = ::GetWindowLong(pActiveView->m_hWnd, GWL_ID);
    ::SetWindowLong(pActiveView->m_hWnd, GWL_ID,
    ::GetWindowLong(pNewView->m_hWnd, GWL_ID));
    ::SetWindowLong(pNewView->m_hWnd, GWL_ID, temp);

    // Display and update the new current view - hide the old one

//((CMDIFrameWnd*) m_pMainWnd)->SetActiveView(pNewView);
    //((CMDIFrameWnd*) m_pMainWnd)->RecalcLayout();

// Attach new view


    return pActiveView;

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