MFC How to update CMDIChildWnd from CDocument

[baumchen]

thanks for the reply. but updateview doesn't solve my problem, as scrollbar doesn't belong to a specific view (it belongs to CMDIChildWnd), and I need to update it too. any idea? thanks!

[Adam Roderick J]

I think you dont need to update the CMDIChildWnd.

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modified on Tuesday, January 19, 2010 12:19 AM

[baumchen]

it is not, it is a CFrameWnd, container of CDocument and CView.

[Adam Roderick J]

I think what you want to achieve is update two scroll views from the document? i.e on update the two views simultanously?

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[baumchen]

exactly. but I don't want to use two scrollbars, is it achievable?

[Adam Roderick J]

I hope you want two Views, both derived from CScrollView? and using a single class. If so then UpdateAllView is what you need.

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[Nelek]

I think you can get 2 CScrollViews and manage who is scrolling (the View is active) when you do the click in one of the scrolls, then from the document you get the new scroll position, give it to the other window using SetScrollPosition with pDoc->ActualPos_2 (assuming you made the click on View1) for the other one and call UpdateAllViews. Or just setting the scroll for both views where you need and call UpdateAllViews when opening a document. Is that more or less what you wanted?

Regards. -------- M.D.V. ;) If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about? Help me to understand what I'm saying, and I'll explain it better to you Rating helpfull answers is nice, but saying thanks can be even nicer.

[baumchen]

Nelek wrote:

Or just setting the scroll for both views where you need

could you give a little bit more info? are both views scrollviews or there is a scrollbar on top of them? if both are scrollviews, how can I set scroll for both views? which class should handle scroll message? thanks!

[baumchen]

i planed to use two views, and attached a scrollbar to CMDIChildWnd (i can't attach scrollbar to CDocument, as it is not a CWnd). UpdateAllView only affect views, but not their container CMDIChildWnd. If using scrollviews, I need to synchronize two scrollbars.....

[Cliff Hatch]

I'm not sure if this exactly fits your requirement, but it is possible to place two views derived from CScrollView into different panes of a splitter window and scroll them together. You need to specify WS_VSCROLL when you create the splitter, otherwise you get a scrollbar for each pane instead of one that works them both. I used WS_HSCROLL and WS_VSCROLL in a recent application to scroll around a matrix and get the row and column headings to scroll along with the body of the matrix. Like this (CMatrixSplitterFrame derived from CMDIChildWnd):

BOOL CMatrixSplitterFrame::OnCreateClient(LPCREATESTRUCT lpcs, CCreateContext* pContext)
{
//Create a splitter with 2 rows and 2 columns
if (!m_SplitterWnd.CreateStatic(this, 2, 2, WS_CHILD | WS_VISIBLE | WS_HSCROLL | WS_VSCROLL)) //Specify WS_HSCROLL and WS_VSCROLL to get one set of horizontal and vertical scrollbars for the splitter window instead of both in each pane.
{
TRACE0("Failed to CreateStaticSplitter\n");
return FALSE;
}

//Add column headings pane
if (!m\_SplitterWnd.CreateView(0, 1,	RUNTIME\_CLASS(CKernelMatrixColHeadView), CSize(2000, CELL\_YSIZE + CELL\_INTER\_GAP + CELL\_INTER\_GAP), pContext))
{
	TRACE0("Failed to create second pane\\n");
	return FALSE;
}
    //etc..

Best Regards Cliff Hatch

[baumchen]

Cliff, thanks for the clue, it is very useful.

BOOL CChildFrame::OnCreateClient(LPCREATESTRUCT, CCreateContext* pContext)
{
// create a splitter with 1 row, 2 columns
if (!m_SplitterController.CreateStatic(this, 1, 2, WS_CHILD | WS_VISIBLE | WS_HSCROLL | WS_VSCROLL))
{
return FALSE;
}

CRect		lRect;

GetClientRect(lRect);

// add the first splitter pane - the default view in column 0
if (!m\_SplitterController.CreateView(0, 0, pContext->m\_pNewViewClass, 
	CSize(lRect.Width() >> 1, lRect.Height()), pContext))
{
	return FALSE;
}

// add the second splitter pane - an input view in column 1
if (!m\_SplitterController.CreateView(0, 1, pContext->m\_pNewViewClass, 
	CSize((lRect.Width() + 1) >> 1, lRect.Height()), pContext))
{
	return FALSE;
}

// activate the input view
SetActiveView((CView\*)m\_SplitterController.GetPane(0, 1));

m\_IsInitialized = TRUE;

return TRUE;

however, it only partly works at here --- there is only one vertical scroll bar, but there are two horizontal scroll bars, did I miss anything? and, how do you answer scroll message? I added it to CChildFrame, which is a subclass of CMDIChildWnd, but it was never called.

afx\_msg void	OnHScroll(UINT nSBCode, UINT nPos, CScrollBar\* pScrollBar);
afx\_msg void	OnVScroll(UINT nSBCode, UINT nPos, CScrollBar\* pScrollBar);

...

BEGIN_MESSAGE_MAP(CChildFrame, CMDIChildWnd)
ON_WM_HSCROLL()
ON_WM_VSCROLL()
ON_WM_MOUSEWHEEL()
ON_WM_SIZE()
END_MESSAGE_MAP()

...

void CChildFrame::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar)
{
CMDIChildWnd::OnHScroll(nSBCode, nPos, pScrollBar);
}

any idea? many thanks!

[Nelek]

It would be using GetScrollPosition in the view that is getting scrolled with the OnScroll and sending it to the other view where you use it with SetScrollPosition before updating all views. Yes, both views should be derived from CScrollView and each one would have its own scrollbar, but you synchronize one when moving the other Here[^] is spoken about SetScrollPos and Here[^] about ScrollToPosition If you manage the actual position of each View in the document, for instance m_pScrollPos_1 and m_pSCrollPos_2, you can call them in your OnDraw and move the actual position of the scroll for this view to the saved point. When you click on a scroll bar just save the new position in the document and call pDoc->UpdateAllViews. It may have a bit delayment between the one and the other whilst synchronising. But it is a possibility

Regards. -------- M.D.V. ;) If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about? Help me to understand what I'm saying, and I'll explain it better to you Rating helpfull answers is nice, but saying thanks can be even nicer.

[Cliff Hatch]

baumchen It looks as though the scrollbars are associated with the panes in a manner that happened to be right for my application, but is perhaps not right for yours. When you specify WS_HSCROLL and WS_VSCROLL you get a horizontal scrollbar on all the panes along the bottom of the window, and a vertical scrollbar on all those on the right hand side. So in my 2x2 display I have 4 scrollbars in total. (Without WS_HSCROLL and WS_VSCROLL there would be 8, 2 for each pane). Sorry, the description in my earlier post was a little misleading. I had forgotten the existence of 2 of my scrollbars because the top row is sized such that it never needs vertical scrolling, and the left column never needs horizontal scrolling - so their bars are always grayed out. It appears that the horizontal scrollbars are shared by all the panes stacked above them, and the vertical ones by all the panes on the row to their left. I haven't been able to test this completely because my top-left pane is a dummy - but this is certainly how the other 3 behave. This would be consistent with your result. In a 1 row x 2 column display, you only get one shared scrollbar - the vertical one. I haven't managed to find any documentation to confirm this, but Technical Note 29 (.Net 2002) has a very short section on shared scroll bars which hints at this arrangment. I didn't write any special handlers. The base classes, CSplitterWnd and CScrollView, managed all the scrolling messages for me. Best Wishes Cliff

[baumchen]

nelek thanks for the detailed info.

[baumchen]

Cliff thanks! looks it is easier to live with two sets of scrollbars.

[Nelek]

You are welcome. I hope it works as you whish. :)

Regards. -------- M.D.V. ;) If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about? Help me to understand what I'm saying, and I'll explain it better to you Rating helpfull answers is nice, but saying thanks can be even nicer.