CGridCtrl in CCtrlView

[mesajflaviu]

I am trying to use CGridCtrl inside of CCtrlView, in an MDI app. And I wrote this:

class CTestGridView : public CCtrlView
{
protected: // create from serialization only
	CTestGridView();
	DECLARE_DYNCREATE(CTestGridView)

// Attributes
public:
	CTestGridDoc* GetDocument() const;
	CGridCtrl& GetGridCtrl() const {return *(CGridCtrl*)this;}
....
}

and in cpp:

CTestGridView::CTestGridView()
	:CCtrlView(GRIDCTRL_CLASSNAME, AFX_WS_DEFAULT_VIEW)
{
	// TODO: add construction code here

	WNDCLASS wndcls;
	//HINSTANCE hInst = AfxGetInstanceHandle();
	HINSTANCE hInst = AfxGetResourceHandle();
	if(! (::GetClassInfo(hInst, GRIDCTRL_CLASSNAME, &wndcls)))
	{
		// otherwise we need to register a new class
		wndcls.style			= CS_DBLCLKS | CS_HREDRAW | CS_VREDRAW;
		wndcls.lpfnWndProc		= ::DefWindowProc;
		wndcls.cbClsExtra		= wndcls.cbWndExtra = 0;
		wndcls.hInstance		= hInst;
		wndcls.hIcon			= NULL;
#ifndef _WIN32_WCE_NO_CURSOR
		wndcls.hCursor		  = AfxGetApp()->LoadStandardCursor(IDC_ARROW);
#else
		wndcls.hCursor		  = 0;
#endif
		wndcls.hbrBackground	= (HBRUSH) (COLOR_3DFACE + 1);
		wndcls.lpszMenuName		= NULL;
		wndcls.lpszClassName	= GRIDCTRL_CLASSNAME;

		if(! AfxRegisterClass(&wndcls))
		{
			AfxThrowResourceException();
		}
	}
}

Until here, it goes without problem ... but when I am trying to use CGridCtrl object inside, I get a crash:

void CTestGridView::OnInitialUpdate() 
{
	CCtrlView::OnInitialUpdate();
	
	CGridCtrl& GridCtrl = (CGridCtrl&)GetGridCtrl();
	GridCtrl.SetRowCount(1); // <-- crash
}

and the error is:

Unhandled exception at 0x77ce0ebc (mfc90d.dll) in TestGrid.exe: 0xC0000005: Access violation reading location 0xfeeefeee.

	if (!AfxIsValidAddress(pOb, pOb->GetRuntimeClass()->m_nObjectSize, FALSE))
	{
		TRACE(traceAppMsg, 0, "ASSERT_VALID fails with illegal pointer.\n");
		if (AfxAssertFailedLine(lpszFileName, nLine))
			AfxDebugBreak();
		return;     // quick escape
	}

This error has been triggered when grid is trying to call:

	TRY
	{
		m_arRowHeights.SetSize(nRows); // <-- here is firing the crash

Is obvious that I done something wrong ... but what ? It is possible what I am trying to do ?

Thank you for any hint/help in solving my task.


P.S. I attach an test app that illustrate the problem.

[ovidiucucu]

class CTestGridView : public CCtrlView
{
    // ...
    CGridCtrl& GetGridCtrl() const {return *(CGridCtrl*)this;} // <--bad
    // ...
}

It crashes because neither CCtrlView nor CTestGridView has a SetRowCount method.
You tried to apply a "trick" used in another CCtrlView-derived classes. It works there because the control classes (CListCtrl, CTreeCtrl, etc.) has methods that only send messages.
Example:

_AFXCMN_INLINE void CListCtrl::SetItemCount(_In_ int nItems)
	{ ASSERT(::IsWindow(m_hWnd)); ::SendMessage(m_hWnd, LVM_SETITEMCOUNT, nItems, 0); }

In case of CGridCtrl do the following:

1. add a member of type CGridCtrl to view class (not necessary to be derived from CCtrlView);
2. call CGridCtrl::Create, in WM_CREATE handler of view class;
3. handle WM_SIZE message in view class and resize the grid control.

[ovidiucucu]

Here is the code:

class CTestGridView : public CView // not CCtrlView
{
    CGridCtrl m_gridCtrl;
    // ...
};

#define GRID_CTRL_ID 1000
// ...

BEGIN_MESSAGE_MAP(CTestGridView, CView)
    // ...
    ON_WM_CREATE()
    ON_WM_SIZE()
END_MESSAGE_MAP()
// ...

int CTestGridView::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
    if (CView::OnCreate(lpCreateStruct) == -1)
        return -1;

    VERIFY(m_gridCtrl.Create(CRect(), this, GRID_CTRL_ID, WS_CHILD | WS_VISIBLE));

    return 0;
}

void CTestGridView::OnSize(UINT nType, int cx, int cy)
{
    CView::OnSize(nType, cx, cy);

    if (m_gridCtrl.GetSafeHwnd())
    {
        m_gridCtrl.SetWindowPos(NULL, 0, 0, cx, cy, SWP_NOZORDER | SWP_NOACTIVATE);
    }
}

void CTestGridView::OnInitialUpdate()
{
    CView::OnInitialUpdate();

    m_gridCtrl.SetRowCount(10);
    m_gridCtrl.SetColumnCount(4);
    // ... and so on.
}

[mesajflaviu]

So, I should understand that I cannot use CGridCtrl inside of CCtrlView in this way ...

I am using right now this technique, to resize an CGridCtrl object over a CView, but I have met a little bug in this case: when I have CDockablePane on an CChildFrame, and CGridCtrl over CView, because CChildFrame are somehow restored under CGridCtrl ... , yes, this is weird, and this happen even if all child frames are maximized, I could switch between open child frames, as I said before, because some CChildFrame are restored ... I know, it is strange, but this is sort of difficult to reproduce this bug ... I will try to made a test app that illustrate this behavior ...

I would like to use the solution from the first post, but I guess it is impossible ...

I will come back with another test app. Thank you.