TScrollBar

Fonte: source/classes/scrllbar.prg

Inherits from: TControl

TScrollBar is a standalone scrollbar control that can be placed independently within a window or dialog. Unlike window automatic scroll bars, TScrollBar is a control object that fires action blocks when the user scrolls, making it suitable for custom browse panels, range selectors, and scrollable containers.

Key DATA Members

DATA	Type	Description
`nMin`	Numeric	Minimum scrollbar value
`nMax`	Numeric	Maximum scrollbar value
`nPgStep`	Numeric	Page-step increment for the scrollbar
`lVertical`	Logical	`.T.` for vertical scrollbar, `.F.` for horizontal
`bGoUp`	Block	Action on small increment (down arrow / right arrow)
`bGoDown`	Block	Action on small decrement
`bGoTop`	Block	Action on reaching the top/left extreme
`bGoBottom`	Block	Action on reaching the bottom/right extreme
`bPageUp`	Block	Action on page increment (click above the thumb)
`bPageDown`	Block	Action on page decrement

Methods

Method	Description
`New( nRow, nCol, nMin, nMax, nPgStep, lVert, oWnd )`	Create a new scrollbar control
`WinNew( nMin, nMax, nPgStep, lVert, oWnd )`	Create a scrollbar using window coordinates
`GoUp()`	Scroll up/right by one step
`GoDown()`	Scroll down/left by one step
`GoTop()`	Scroll to the minimum position
`GoBottom()`	Scroll to the maximum position
`PageUp()`	Scroll up by one page step
`PageDown()`	Scroll down by one page step
`SetPos( n )`	Set the thumb position to `n`
`GetPos()`	Return the current thumb position

Example: Vertical Scrollbar Linked to Browse

#include "FiveWin.ch"

function Main()

   local oWnd, oScroll, nPos := 1

   DEFINE WINDOW oWnd TITLE "ScrollBar Demo" SIZE 300, 300

   @ 10, 260 SCROLLBAR oScroll ;
      RANGE 1, 100 ;
      PAGE 10 ;
      VERTICAL OF oWnd ;
      ON UP nPos-- ;
      ON DOWN nPos++

   ACTIVATE WINDOW oWnd CENTERED

return nil

Notes

Use VERTICAL clause for a vertical scrollbar; omit it or use HORIZONTAL for a horizontal scrollbar.
The RANGE clause sets nMin and nMax. The PAGE clause sets nPgStep.
Action blocks (ON UP, ON DOWN, ON PAGEUP, ON PAGEDN) fire when the user interacts with the corresponding scrollbar regions.
TScrollBar is ideal for custom scrolling in browse-like controls where the window's built-in scroll bars are not used.

TScrollBar

Key DATA Members

Methods

Example: Vertical Scrollbar Linked to Browse

Notes

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