Re: Switching views : season 2

Hi,

In my SDI application I have defined a CBaseFrame deriving from
CFrameWnd and that allow me to switch between view dynamically
created.Here is the code I suse

//CREATE_ONCE means view is create once and never deleted when switching
//CREATE_AND_DESTROY means views are deleted/recreated on switch
CBaseFrame::stViewInfo CBaseFrame::m_ViewInfo[] =
{
        { IDD_MAIN_FORM, CBaseFrame::CREATE_ONCE, AFX_IDW_PANE_FIRST + 0, NULL },
        { IDD_WELCOME_DLG, CBaseFrame::CREATE_AND_DESTROY,
AFX_IDW_PANE_FIRST + 1, NULL },
        { IDD_WIZZARD_DLG, CBaseFrame::CREATE_AND_DESTROY, AFX_IDW_PANE_FIRST
+ 2, NULL },
        { IDD_OPTIONS_DLG, CBaseFrame::CREATE_AND_DESTROY, AFX_IDW_PANE_FIRST
+ 3, NULL },
        { IDD_CNX_DLG, CBaseFrame::CREATE_AND_DESTROY, AFX_IDW_PANE_FIRST +
4, NULL },
        { IDD_SCHEDULE_DLG, CBaseFrame::CREATE_AND_DESTROY, AFX_IDW_PANE_FIRST
+ 5, NULL },
        { IDD_HISTORY_DLG, CBaseFrame::CREATE_AND_DESTROY, AFX_IDW_PANE_FIRST
+ 6, NULL },
        { IDD_ABOUT_DLG, CBaseFrame::CREATE_AND_DESTROY, AFX_IDW_PANE_FIRST +
7, NULL },

};

LRESULT CBaseFrame::OnSwitchView( WPARAM wParam, LPARAM lParam )
//CView* CBaseFrame::SwitchView( UINT a_ViewId )
{
        int iCurViewIdx = 0;
        int iNewViewIdx = 0;
        CView* pCurView = NULL;
        CView* pNewView = NULL;
        BOOL bDestroyOldView = FALSE;
        UINT ViewId = (UINT) wParam;

        //Get current active view
        pCurView = m_pFrame->GetActiveView();
        TRACE( _T("CViewMgr::SwitchView : pCurView = 0x%x\r\n"), pCurView );
        if ( pCurView == NULL)
                return 0L;

        //Get Curview and NextView index
        iCurViewIdx = GetIndexFromView( pCurView );
        iNewViewIdx = GetIndexFromId( wParam );
        if ((iCurViewIdx == -1) || (iNewViewIdx == -1))
                return 0L;

        pNewView = m_ViewInfo[iNewViewIdx].pView;

        // View is already displayed
        if ( pNewView == pCurView ){
                return 0L/*pCurView*/;
        }

        // New view is NULL - we must create it
        if ( pNewView == NULL ){
                pNewView = CreateView( ViewId, iNewViewIdx);
                TRACE( _T("pNewView = 0x%x\r\n"), pNewView );
                if (pNewView != NULL){
                        // Save new created view
                        m_ViewInfo[iNewViewIdx].pView = pNewView;
                }
        }//pView == NULL

        //Make sure that the document won't be destroyed when the view is
destroyed.
        //m_bAutoDelete is a public, but non-documented member of CDocument.
        CDocument* pCurrentDoc = m_pFrame->GetActiveDocument();
        pCurrentDoc->m_bAutoDelete = FALSE;

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

        // Hide Old view
        pCurView->ShowWindow(SW_HIDE);

        //OnInitialUpdate() is not called as a result of calling CreateView()
above.
        //It is not always called by the framework, so it is called here:
        pNewView->OnInitialUpdate();

        // Now show the new view
        pNewView->ShowWindow(SW_SHOW);
        m_pFrame->SetActiveView(pNewView);
        m_pFrame->RecalcLayout();
        pNewView->Invalidate();

        // try to destroy old view
        if ( m_ViewInfo[iCurViewIdx].eCreationMode == CREATE_AND_DESTROY){
                pCurView->DestroyWindow();
                m_ViewInfo[iCurViewIdx].pView = NULL;
        }

        return 0L/*pNewView*/;

}

The problem happens when I try to destroy the old view :

// try to destroy old view
        if ( m_ViewInfo[iCurViewIdx].eCreationMode == CREATE_AND_DESTROY){
                pCurView->DestroyWindow();
                m_ViewInfo[iCurViewIdx].pView = NULL;
        }

I have the following assert :

Assert wincore.cpp(windows CE) 442
LRESULT CALLBACK
AfxWndProc(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam)
{
        // special message which identifies the window as using AfxWndProc
        if (nMsg == WM_QUERYAFXWNDPROC)
                return 1;

        // all other messages route through message map
        CWnd* pWnd = CWnd::FromHandlePermanent(hWnd);
        ASSERT(pWnd != NULL && pWnd->m_hWnd == hWnd);

...

}