TTrackBar class

In unit ComCtrls

TTrackBar: a device which allows the user to determine the value of a variable using a quasi-analog slider.

Declaration

pascal

TTrackBar = class(TCustomTrackBar)

Inheritance

Description

TTrackBar: a device which allows the user to determine the value of a variable using a quasi-analog slider.

The device looks like a slider-potentiometer control on a hi-fi amplifier and consists of a slider which can be moved along a bar using the mouse. Tick marks can be displayed along one or both edges, giving an indication of the proportion of the maximum value of the controlled variable that is being selected.

The Position property indicates the distance along the bar that the slider has been placed, either by the program or by mouse capture and movement.

In the example, movement of the slider is detected and shown in the associated TProgressBar.

Example: `TrackBarEx.pas`

pascal

 
procedure TForm1.TrackBar1Change(Sender: TObject);
begin
  ProgressBar1.Position := (TrackBar1.Position)*10
end;

Properties

`Align`	published	Specifies the placement of the control on its Parent control.
`Anchors`	published	The set of anchor definitions for this control.
`BorderSpacing`	published	Determines the inner and outer border spacing for this control.
`Color`	published	The background color for the control.
`Constraints`	published	Contains the minimum and maximum Width and Height for the control.
`DragCursor`	published	The cursor shape shown during a drag operation.
`DragMode`	published	Determines how a drag operation is started for the control.
`Enabled`	published	Determines whether the control responds to mouse or keyboard input.
`Font`	published	The font to be used for text display in this control.
`Frequency`	published	Indicates the frequency for the tick marks displayed on the control.
`Hint`	published	The text to show in the Hint window for the control.
`LineSize`	published	Increment (or decrement) applied to the slider position when an arrow key is pressed.
`Max`	published	Maximum value allowed in the Position for the track bar.
`Min`	published	Minimum value allowed in the Position for the track bar.
`Orientation`	published	Indicates the horizontal or vertical orientation for the track bar control.
`PageSize`	published	The increment (or decrement) applied to the slider Position when the PageUp or PageDown key is pressed.
`ParentColor`	published	Use the Color from the Parent control, when enabled.
`ParentFont`	published	Indicates if the Font from the Parent control is used in the control.
`ParentShowHint`	published	If True, the value of ShowHint for the control will be the same as the one from the Parent. Default is True.
`PopupMenu`	published	A context-sensitive menu that pops up when the right mouse button is clicked over this control.
`Position`	published	Location of the slider on the track bar between the Min and Max values.
`Reversed`	published	Set to True to display values on the track bar in reverse order.
`ScalePos`	published	Position where the scale is displayed for the track bar control.
`SelEnd`	published	Ending value for the selection range on the track bar control.
`SelStart`	published	Starting value for the selection range on the track bar control.
`ShowHint`	published	Enables Hint display for the control.
`ShowSelRange`	published	Enables or disables a highlighted selection range with tick marks using the values in SelStart and SelEnd.
`TabOrder`	published	Indicates the navigation order for the control when the user presses the Tab or Shift+Tab key.
`TabStop`	published	Enables or disables navigation using the Tab key.
`TickMarks`	published	Position for the tick marks relative to the slider in the track bar.
`TickStyle`	published	Indicates the tick mark drawing style for the control.
`Visible`	published	Allows the control, and all of its children, to be displayed or hidden.

Events

`OnChange`	published	Event handler signalled when the Position in the control has been changed.
`OnChangeBounds`	published	Event handler signalled when the Bounds for the control have been changed.
`OnClick`	published	Notification handler for mouse clicks.
`OnContextPopup`	published	Invoked when a context-sensitive pop-up menu is requested.
`OnDragDrop`	published	Event handler signalled when an object is dropped onto the control.
`OnDragOver`	published	Event handler signalled when a control is dragged over the control instance.
`OnEndDrag`	published	Event handler signalled for the end of a drag-drop operation.
`OnEnter`	published	Event handler signalled when the control receives focus.
`OnExit`	published	Event handler signalled when the control loses focus.
`OnMouseDown`	published	Event handler signalled when a mouse down event is handled for the control.
`OnMouseEnter`	published	Event handler signalled when the mouse pointer has entered the control.
`OnMouseLeave`	published	Event handler signalled when the mouse pointer has left the control.
`OnMouseMove`	published	Event handler signalled when the mouse pointer is moved in the control.
`OnMouseUp`	published	Event handler signalled when a mouse up event is handled for the control.
`OnMouseWheel`	published	Event handler for mouse wheel turned.
`OnMouseWheelDown`	published	Event handler signalled for a downward movement of the mouse wheel.
`OnMouseWheelUp`	published	Event handler signalled for an upward movement of the mouse wheel.
`OnMouseWheelHorz`	published	Event handler signalled for a horizontal movement of the mouse wheel.
`OnMouseWheelLeft`	published	Event handler signalled for a leftward movement of the mouse wheel.
`OnMouseWheelRight`	published	Event handler signalled for a rightward movement of the mouse wheel.
`OnKeyDown`	published	Event handler signalled for key down keyboard events.
`OnKeyPress`	published	Event handler signalled for character data entered by the user.
`OnKeyUp`	published	Event handler signalled when a key up event has occurred for the control.
`OnResize`	published	Notification handler for a resize of the control.
`OnStartDrag`	published	Event handler signalled for the start of a dragging operation.
`OnUTF8KeyPress`	published	Handler for a character entered by the user.