CTabView - CView's HWND is NULL

I'm using the Feature Pack CTabView, and I noticed that when the view is added using AddView with the following code CView's HWND is NULL when I try and access each of the CView1,CView2, etc.

Code:

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int CMyTabView::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
    if (CTabView::OnCreate(lpCreateStruct) == -1)
        return -1;
    AddView (RUNTIME_CLASS (CView1), _T("Simple"),                100);
    AddView (RUNTIME_CLASS (CView2), _T("Pair"),                101);
    AddView (RUNTIME_CLASS (CView3), _T("Data"),                102);

    return 0;
}

I think the user has to click the view's tab before the CTabView assigns an HWND.  Is there a way to force CTabview to give each CView an HWND when the view is added?

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I guess the behavior of CTabView::AddView is the same as the one of CPropertySheet::AddPage.
So there is no need to create a window being later shown (after a user selects it or you call CTabView::SetActiveView) before it will be needed to be shown.
Why do you need to have each CView already created when the view is added?

Quote:

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Originally Posted by VictorN

I guess the behavior of CTabView::AddView is the same as the one of CPropertySheet::AddPage.
So there is no need to create a window being later shown (after a user selects it or you call CTabView::SetActiveView) before it will be needed to be shown.
Why do you need to have each CView already created when the view is added?

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I have a clistctrl on the view that I want to update from a database. The database updated the view before it is displayed. So I want the view to have an HWND so I can access its functions.

Why not update "a clistctrl n the view" in the CView::OnInitialUpdate override? It is called before the view is displayed.

According to the code below all views are created immediately inside AddView and later can be accessible via document object:

Code:

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int CTabView::AddView(CRuntimeClass* pViewClass, const CString& strViewLabel, int iIndex /*= -1*/, CCreateContext* pContext/* = NULL*/)
{
        ASSERT_VALID(this);
        ENSURE(pViewClass != NULL);
        ENSURE(pViewClass->IsDerivedFrom(RUNTIME_CLASS(CView)));

        CView* pView = DYNAMIC_DOWNCAST(CView, pViewClass->CreateObject());
        ASSERT_VALID(pView);

        if (!pView->Create(NULL, _T(""), WS_CHILD | WS_VISIBLE, CRect(0, 0, 0, 0), &m_wndTabs, (UINT) -1, pContext))
        {
                TRACE1("CTabView:Failed to create view '%s'\n", pViewClass->m_lpszClassName);
                return -1;
        }

        CDocument* pDoc = GetDocument();
        if (pDoc != NULL)
        {
                ASSERT_VALID(pDoc);

                BOOL bFound = FALSE;
                for (POSITION pos = pDoc->GetFirstViewPosition(); !bFound && pos != NULL;)
                {
                        if (pDoc->GetNextView(pos) == pView)
                        {
                                bFound = TRUE;
                        }
                }

                if (!bFound)
                {
                        pDoc->AddView(pView);
                }
        }

        m_wndTabs.InsertTab(pView, strViewLabel, iIndex);

        int nTabs = m_wndTabs.GetTabsNum();
        return nTabs - 1;
}

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Thanks Igor, that makes sense. Where does that code come from?

From <your VS folder>\VC\atlmfc\src\mfc\afxtabview.cpp

Got it, I added the function to my CMyTabView class and now I have the HWND.

Thanks

Quote:

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Originally Posted by cbpetro

Got it, I added the function to my CMyTabView class and now I have the HWND.

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But which AddView did you call in the CMyTabView::OnCreate() handler? :confused:

Quote:

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Originally Posted by VictorN

But which AddView did you call in the CMyTabView::OnCreate() handler? :confused:

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The AddView code that Igor provided, I had to change my AddView call from...


AddView (RUNTIME_CLASS (CView1), _T("Simple"), 100);

to...

AddView (RUNTIME_CLASS (CView1), _T("Simple"), 100 , NULL);

Do you have your own AddView method in CMyTabView class?
Otherwise there would be no difference in these two calls

Quote:

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Code:

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AddView (RUNTIME_CLASS (CView1), _T("Simple"),        100);

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and

Code:

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AddView (RUNTIME_CLASS (CView1), _T("Simple"),        100 , NULL);

---

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because the forth parameter of CTabView::AddView has default value NULL:

Quote:

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CTabView::AddView


Adds a view to the tab control.

Code:

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int AddView(
  CRuntimeClass* pViewClass,
  const CString& strViewLabel,
  int iIndex=-1,
  CCreateContext* pContext=NULL
);

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Quote:

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Originally Posted by VictorN

Do you have your own AddView method in CMyTabView class?
Otherwise there would be no difference in these two callsbecause the forth parameter of CTabView::AddView has default value NULL:

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Correct, but when I use the default AddView I never have the HWND of each CView, unless I call OnActivateView or something as I am not use the doc/view architecture. If I use the custom AddView, I see the CView being created and I can customize the AddView further by adding each CView to a CSimpleArray in my CMyTabView class.

Now I have access to each CView in CMyTabView from anywhere in my program.