Directives

V_SCROLLBAR

Create/Control Vertical Scrollbar

Formats

1. Define/Create:	V_SCROLLBAR ctl_id, @(col,ln,wth,ht) [,ctrlopt]
2. Define at Edge of Window:	V_SCROLLBAR ctl_id WINDOW [,ctrlopt]
3. Delete:	V_SCROLLBAR REMOVE ctl_id [,ERR=stmtref]
4. Disable/Enable:	V_SCROLLBAR { ENABLE \| DISABLE } ctl_id [,ERR=stmtref]
5. Set Focus:	V_SCROLLBAR GOTO ctl_id [,ERR=stmtref]
6. Read Setting:	V_SCROLLBAR READ ctl_id, setting, max [,rgn_chg] [,arrow_chg] [,ERR=stmtref]
7. Update:	V_SCROLLBAR WRITE ctl_id, marker, max [,ERR=stmtref]
8. Hide/Show:	V_SCROLLBAR { HIDE \| SHOW } ctl_id [,ERR=stmtref]

Where

@(col,ln,wth,ht)

Position and size of the vertical scrollbar region. Numeric expressions. Column and line coordinates for top left corner, width in number of columns and height in number of lines.

arrow_chg

Amount to increase/decrease the V_SCROLLBAR setting when the user selects the arrow at the top/bottom edge of the vertical scrollbar. Numeric expression. (Default: 1)

ctl_id

Unique logical identifier for a vertical scrollbar (any integer -32000 to +32000). Avoid integers that conflict with keyboard definitions (e.g. 4 cancels CTL=4 for the F4 key) or Negative CTL Definitions.

ctrlopt

Control options. The only supported option for V_SCROLLBAR is:

OPT=char$

Single character parameter/option:

"D"	Disabled. User cannot access the scrollbar.
"d"	Scrollbar is permanently disabled (cannot be enabled).
"H"	Hide. Do not display the scrollbar.
"A"	Auto. Generate CTL signal for each movement.
"s"	Scroll. Allow scroll within resizable/scrollable dialogue box.

marker

Relative position to set as the V_SCROLLBAR marker. Numeric expression between 1 and the maximum.

max

Logical maximum value of the V_SCROLLBAR. Numeric expression.

rgn_chg

Amount to increase/decrease the V_SCROLLBAR setting when the user selects the region left/right of the marker. Numeric expression. (Default: max/width)

setting

Numeric variable to receive the current scrollbar setting.

stmtref

Program line number or statement label to which to transfer control.

Description

Use the V_SCROLLBAR directive to create a vertical scrollbar control object on the screen. Your program logic can read and adjust a value by increments to control logical record position within a file every time the user moves the vertical scrollbar.

Use either V_SCROLLBAR Format 1 or Format 2 to define or create a vertical scrollbar. The value in ctl_id gives the vertical scrollbar a unique identifier. This is generated as a CTL value whenever the vertical scrollbar is selected and changed.

Vertical Scrollbar Properties

The Apostrophe Operator can be used with the unique logical identifier (ctl_id) to dynamically read and alter a wide variety of control attributes (properties) directly from the programming language.

See V_SCROLLBAR Properties for the list of properties available for manipulating a vertical scrollbar.

Format 1

Create

V_SCROLLBAR ctl_id,@(col,ln,wth,ht)[,ctrlopt]

Use this format to create a vertical scrollbar inside the current window.

Example:

v_scrollbar 100,@(70,2,2,20)

This example defines a vertical scrollbar that is 2 columns wide, 20 lines high, starting at column 70 on line 2. Whenever the scrollbar is selected, a CTL=100 is generated.

Format 2

Define at Edge of Window

V_SCROLLBAR ctl_id WINDOW[,ctrlopt]

Use the V_SCROLLBAR format with WINDOW to create a vertical scrollbar at the edge of the window.

Format 3

Delete

V_SCROLLBAR REMOVE ctl_id[,ERR=stmtref]

Use the V_SCROLLBAR REMOVE format to delete the vertical scrollbar.

Format 4

Disable/Enable

V_SCROLLBAR {DISABLE | ENABLE} ctl_id [,ERR=stmtref]

Use the V_SCROLLBAR DISABLE format to gray out a vertical scrollbar so that it will be visible but inaccessible to users. To reactivate it, use V_SCROLLBAR ENABLE.

Format 5

Set Focus

V_SCROLLBAR GOTO ctl_id[,ERR=stmtref]

Use the V_SCROLLBAR GOTO format to set the focus on the vertical scrollbar, ready for the user's next action.

Format 6

Read Setting

V_SCROLLBAR READ ctl_id, setting, max,[rgn_chg][,arrow_chg][,ERR=stmtref]

Use this format to read the current setting of the vertical scrollbar. Once a new position is selected, you must read it before your application can use the value to update the actual V_SCROLLBAR position.

Example:

0120 v_scrollbar read 100,X,1000
0130 v_scrollbar write 100,X,1000

Line 0120 reads the scrollbar position relative to 1000 and line 0130 updates the settings.

Format 7

Update

V_SCROLLBAR WRITE ctl_id,marker,max[,ERR=stmtref]

Use the V_SCROLLBAR WRITE format to update or write the V_SCROLLBAR settings.

Format 8

Hide/Show

V_SCROLLBAR {HIDE | SHOW} ctl_id[,ERR=stmtref]

With the V_SCROLLBAR HIDE format, the scrollbar remains active but is not displayed. It is still accessible programmatically. Use the SHOW format to restore the display and user access.

Example

0100 ! 100 - Vertical Scrollbar Example
0110 let VAL=1,MX=400,BJMP=25,SJMP=1
0120 v_scrollbar 101,@(6,14,1,10)
0130 v_scrollbar 102,@(15,14,2,10)
0140 v_scrollbar 103,@(25,14,3,10)
0150 v_scrollbar 104 window
0160 input (0,hlp="V_SCROLLBAR")@(40,18),"Select...: ",'CL',X$
0170 if ctl<101 or ctl>104 then goto 0210
0180 v_scrollbar read ctl,VAL,MX,BJMP,SJMP
0190 v_scrollbar write ctl,VAL,MX
0200 print @(40,19),"Selection:",ctl,":",str(VAL),'CL',; goto 0160
0210 if ctl=0 or ctl>=3 then stop else goto 0160