VTrackBar control

Like a scroll bar, a trackbar is used as a scrolling control, but clicking on the trackbar slider moves it in discrete increments instead of continuously. The VTrackBar control has a series of tick marks to the right of the trackbar channel.

To enable this control to be used properly from the keyboard, you must add code to the LineDown, LineUp, PageDown, and PageUp events. The code you add should change the slider Position property by the appropriate value and then pass the new slider position to the object or objects you associate with the trackbar control. You must code the Moved event if you want the trackbar control to pass on the slider position after the slider is dragged with a mouse.

Usage note

Use a trackbar when you want the user to select a discrete value. For example, you might use a trackbar to enable a user to select a timer interval or the size of a window.

Properties

VTrackBar property

Datatype

Description

AccessibleDescription

String

A description of the control and/or its purpose for use by accessibility tools such as readers for visually impaired users.

AccessibleName

String

A label that briefly describes the control, such as the text in a button or the name of a menu item.

AccessibleRole

AccessibleRole (enumerated)

Describes what kind of user interface element the control is.

BringToTop

Boolean

Specifies whether PowerBuilder moves the control to the top of the front-to-back order. Values are:

TRUE -- Control moved to top.

FALSE -- Control not moved to top.

ClassDefinition

PowerObject

An object of type PowerObject containing information about the class definition of the object or control.

DragAuto

Boolean

Specifies whether PowerBuilder puts the control automatically into Drag mode. Values are:

TRUE  -- When the control is clicked, the control is automatically in Drag mode.

FALSE  -- When the control is clicked, the control is not automatically in Drag mode. You have to manually put the control into Drag mode by using the Drag function.

DragIcon

String

Specifies the name of the stock icon or the file containing the icon you want to display when the user drags the control (the ICO file). The default icon is a box the size of the control.

When the user drags the control, the icon displays when the control is over an area in which the control can be dropped (a valid drop area). When the control is over an area that is not a valid drop area, the No-Drop icon displays.

Height

Integer

Specifies the height of the control, in PowerBuilder units.

LineSize

Integer

Specifies how far the slider moves in response to keyboard input from the arrow keys.

MaxPosition

Integer

Specifies the value of the Position property when the slider is at the bottom of the control.

MinPosition

Integer

Specifies the value of the Position property when the slider is at the top of the control.

PageSize

Integer

Specifies how far the slider moves in response to keyboard or mouse input. Setting PageSize to 1 indicates moving 1 increment in the range of values.

Pointer

String

Specifies the name of the stock pointer or file containing the pointer used for the control.

Position

Integer

Specifies a value between MinPosition and MaxPosition specifying the position of the slider.

Slider

Boolean

Specifies whether or not the trackbar contains a slider.

SliderSize

Integer

Specifies the size of the slider on the trackbar.

TabOrder

Integer

Specifies the tab value of the control within the window (0 means the user cannot tab to the control).

Tag

String

Specifies the tag value assigned to the control.

TickFrequency

Integer

Specifies tick mark frequency. Setting TickFrequency to 1 indicates 1 tick mark for each increment in the trackbar range of values.

TickMarks

VTickMarks (enumerated)

Specifies where tickmarks should be displayed. Values are:

VTicksOnRight!

VTicksOnLeft!

VTicksOnBoth!

VTicksOnNeither!

Visible

Boolean

Specifies whether the control is visible. Values are:

TRUE -- Control is visible.

FALSE -- Control is not visible.

Width

Integer

Specifies the width of the control, in PowerBuilder units.

X

Integer

Specifies the X position (the distance from the left edge of the window), in PowerBuilder units.

Y

Integer

Specifies the Y position (the distance from the top of the window), in PowerBuilder units.


Events

VTrackBar event

Occurs

Constructor

Immediately before the Open event occurs in the window

Destructor

Immediately after the Close event occurs in the window

DragDrop

When a dragged control is dropped on the control

DragEnter

When a dragged control enters the control

DragLeave

When a dragged control leaves the control

DragWithin

When a dragged control is within the control

GetFocus

Just before the control receives focus (before it is selected and becomes active)

Help

When the user presses the F1 key or drags the context help button (question mark) from the title bar to a menu item or control

LineDown

When the down arrow key is clicked

LineUp

When the up arrow key is clicked

LoseFocus

When the control loses focus (becomes inactive)

Moved

When the slider is moved (use the Position property to determine the new location)

Other

When a Windows message occurs that is not a PowerBuilder event

PageDown

When the Page Down key is clicked or when mouse clicks are made below the slider in the trackbar channel

PageUp

When the Page Up key is clicked or when mouse clicks are made above the slider in the trackbar channel

RButtonDown

When the right mouse button is pressed on the control


Functions

VTrackBar function

Datatype returned

Description

ClassName

String

Returns the name assigned to the control.

Drag

Integer

Starts or ends the dragging of the control.

GetContextService

Integer

Creates a reference to a context-specific instance of the specified service.

GetParent

PowerObject

Returns a reference to the name of the parent object.

Hide

Integer

Makes the control invisible.

Move

Integer

Moves the control to a specified location.

PointerX

Integer

Returns the distance of the pointer from the left edge of the control.

PointerY

Integer

Returns the distance of the pointer from the top of the control.

PostEvent

Boolean

Adds an event to the end of the message queue for control.

Print

Integer

Prints the control.

Resize

Integer

Changes the size of the control.

SelectionRange

Integer

Sets a selection range for the trackbar. When you select a range, a blue line is drawn in the channel of the trackbar and two arrows are drawn where the tickmarks are placed to indicate the beginning and end of the selection range.

SetFocus

Integer

Sets the focus to the control.

SetPosition

Integer

Specifies the position of the control in the front-to-back order of the window.

SetRedraw

Integer

Controls automatic redrawing of the control after each change in its properties.

Show

Integer

Makes the control visible.

TriggerEvent

Integer

Triggers a specified event in the control and executes the script for the event.

TypeOf

Object

Returns the type of the control.