Scrollbar control

[Cezary Zielinski]

Hi forum!

I need advice how to make scrollbar control (prefferably in DDT).
I need to make special format file viewer and scrollbar seems to be the best for scrolling it in window. I can't use textbox because of file size (in text form up to 10 megs). My idea is to read and show only part of file with displaying it's contents in separated text boxes (columns).

Thanks in advance

Cezary Zielinski

[Semen Matusovski]

Cezary --
Look http://www.powerbasic.com/files/pub/pbwin/petzold.zip

Chapter 8, color1.bas

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[Lance Edmonds]

On this subject, it's worth noting that there was an omission in the PB/DLL help file: CONTROL ADD SCROLLBAR.



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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Borje Hagsten]

"On this subject, it's worth noting that there was an omission in
the PB/DLL help file: CONTROL ADD SCROLLBAR."

Interesting. Is there an updated helpfile available somewhere, or
a textfile with corrections for it?

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[Lance Edmonds]

Not currently, sorry.


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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Cezary Zielinski]

Thanks Semen, thanks everybody. I declared scroll bar in this manner:

CONTROL ADD "scrollbar", hDlg, %ID_SCRL, "", x, y, xx, yy, _
%WS_CHILD OR %WS_VISIBLE OR %WS_TABSTOP OR %SBS_VERT

Events are handled like in Petzold's example.

Thanks again

Cezary

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[Cezary Zielinski]

Hi!

I meet another problem with scrollbar. When I try to retrieve thumb position:

Case %SB_THUMBPOSITION
pos = GetScrollPos(sbCh, %SB_CTL)

then I get previous position (before moving thumb).
I can't use:

pos = HIWRD(CBWPARAM)

because it returns only 16 bit value.

Any idea?

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[E B Knoppert]

Can DDT set a scrollbar (+ dialogScrollbar)?



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[Fred Oxenby]

Note The GetScrollPos function is provided for backward compatibility.
New applications should use the GetScrollInfo function.
The GetScrollInfo function enables applications to use 32-bit scroll positions.
Although the messages that indicate scroll-bar position,
WM_HSCROLL and WM_VSCROLL, provide only 16 bits of position data,
the functions SetScrollInfo and GetScrollInfo provide 32 bits of scroll-bar position data.
Thus, an application can call GetScrollInfo while processing
either the WM_HSCROLL or WM_VSCROLL messages to obtain 32-bit scroll-bar position data.
To get the 32-bit position of the scroll box (thumb) during a SB_THUMBTRACK
request code in a WM_HSCROLL or WM_VSCROLL message, call GetScrollInfo with the
SIF_TRACKPOS value in the fMask member of the SCROLLINFO structure.
The function returns the tracking position of the scroll box in the nTrackPos member
of the SCROLLINFO structure. This allows you to get the position of the scroll box
as the user moves it.

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Fred
mailto:[email protected][email protected]</A>
http://www.oxenby.se



[This message has been edited by Fred Oxenby (edited February 09, 2000).]

[Cezary Zielinski]

Thanks Fred!

I tried to read nPos, not nTrackPos - and it was mistake.

E B

I declared scroll bar control with:

CONTROL ADD SCROLLBAR, hDlg, %ID_SCRL, "", x, y, xx, yy, _
%WS_CHILD OR %WS_VISIBLE OR %WS_TABSTOP OR %SBS_VERT

and in callback function:

STATIC si AS SCROLLINFO

SELECT CASE CBMSG
CASE %WM_INITDIALOG
CONTROL HANDLE CBHNDL, %ID_SCRL TO sbch
si.cbSize = SIZEOF(si)
si.fMask = %SIF_ALL
si.nMin = pozP
si.nMax = pozK 'MAX(LOF(rf) - %Wys * DlRek, pozP)
si.nPage = %Wys * DlRek
si.nPos = pozP
SetScrollInfo sbch, %SB_CTL, si, %True
CASE %WM_VSCROLL
SELECT CASE CBCTL
CASE %SB_LINEUP
CASE %SB_LINEDOWN
.......

------------

It is "alone" control, not associated with any textbox control.

Cezary

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[E B Knoppert]

Yes, but you used WINAPI with DDT.

My question was (for PB) if there where DDT-commands to set/maintain the scrollbar values..

Thanks,



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[Lance Edmonds]

At this time you must use the appropriate scrollbar API calls, such as SetScrollInfo(), etc.

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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>