Maximum size of scrollbars

pgrohs

Does anyone know an easy way to overcome the problem with the SRT_MAX limit of scrollbars? :confused: -- modified at 12:08 Tuesday 7th March, 2006

Gary R Wheeler

Use SetScrollInfo()[^].

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pgrohs

This is my code: void CEditor::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar) { SCROLLINFO ScrollInfo; ScrollInfo.cbSize = sizeof(SCROLLINFO); ScrollInfo.fMask = SIF_POS | SIF_RANGE; GetScrollInfo(SB_VERT, &ScrollInfo); switch(nSBCode){ ... case SB_THUMBPOSITION: ScrollInfo.nPos = nPos; break; case SB_THUMBTRACK: ScrollInfo.nPos = nPos; break; } SetVScroll(ScrollInfo.nPos); CWnd::OnVScroll(nSBCode, nPos, pScrollBar); } The problem is that nPos does not become bigger than SRT_MAX. This is because nPos comes from the high-order word of the wParam of the message WM_VSCROLL. So it is just a short value that is casted to an integer. Is there another way to get the current position of the scroll box? Thanks

Gary R Wheeler

You have to initialize the scroll bar at some point with a call to SetScrollInfo. My guess would be you want to do this in your CEditor::OnCreate handler. The nPos value you are seeing in your OnVScroll handler varies between the values of nMin and nMax in the SCROLLINFO structure.

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pgrohs

Thank you for your help, but I think I have to describe the problem more detailed. The scrollbar works fine when I move the scroll box with SB_PAGEDOWN or SB_LINEDOWN because in this case I do not need nPos. But when I react on SB_THUMBTRACK or SB_THUMBPOSITION I need nPos. So when I move the scroll box with the mouse to a position that is bigger than SRT_MAX nPos becomes zero and the scroll box jumps back to the top. Again: this is only the case if the scroll box is directly moved with the mouse. When I click on the scroll arrows everything works fine. So what I need is a way to find out where the user has moved the scroll box when it is above SRT_MAX. Thanks

Gary R Wheeler

When handling SB_THUMBTRACK, you need to look at the nTrackPos member of the SCROLLINFO structure, not nPos.

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pgrohs

Thank you very much. It works. MSDN is such a great thing, but it happens the you do not to see the wood for the trees.:rolleyes: