[Overview][Constants][Types][Classes][Procedures and functions][Index] | Reference for unit 'ComCtrls' (#lcl)

# TCustomTrackBar

[Properties (by Name)] [Methods (by Name)] [Events (by Name)]

TCustomTrackBar - the base class for TTrackBar.

## Declaration

Source position: comctrls.pp line 2734

`type TCustomTrackBar = class(TWinControl)`
`protected`
`class procedure WSRegisterClass; override;` |  | Registers this component class with the current WidgetSet.
`procedure ApplyChanges;` |  | Sends message to update the visual appearance of the object.
`procedure Changed; virtual;` |  | Signals the OnChange event handler (when assigned).
`procedure DoChange(); message;` |  | Performs actions needed to update the position for the track bar and signal the OnChange event.
`procedure FixParams();` |  | Normalizes values in Min and Max, and ensures that Position is in range.
`class function GetControlClassDefaultSize; override;` |  | GetControlClassDefaultSize - returns its own defaults, overriding the inherited values.
`procedure InitializeWnd; override;` |  | Copies cached control properties to the newly created widget.
`procedure Loaded; override;` |  | Performs actions when a component has been loaded during LCL streaming.
`procedure ShouldAutoAdjust(); override;` |  | Determines whether the width and height for the control are automatically resized.
`public`
`constructor Create(); override;` |  | Constructor for the class instance.
`procedure SetTick();` |  | Sets the position for the tick mark displayed on the track bar control.
`procedure SetParams();` |  | Sets the values in the Position, Min, and Max properties.
`published`
`property AutoSize: Boolean;` |  | Allows automatic adjustment of the size for the control, according to its content.
`property Frequency: Integer; [rw]` |  | Indicates the frequency for the tick marks displayed on the control.
`property LineSize: Integer; [rw]` |  | Increment (or decrement) applied to the slider position when an arrow key is pressed.
`property Max: Integer; [rw]` |  | Maximum value allowed in the Position for the track bar.
`property Min: Integer; [rw]` |  | Minimum value allowed in the Position for the track bar.
`property Orientation: TTrackBarOrientation; [rw]` |  | Indicates the horizontal or vertical orientation for the track bar control.
`property PageSize: Integer; [rw]` |  | The increment (or decrement) applied to the slider Position when the PageUp or PageDown key is pressed.
`property Position: Integer; [rw]` |  | Location of the slider on the track bar between the Min and Max values.
`property Reversed: Boolean; [rw]` |  | Set to True to display values on the track bar in reverse order.
`property ScalePos: TTrackBarScalePos; [rw]` |  | Position where the scale is displayed for the track bar control.
`property SelEnd: Integer; [rw]` |  | Ending value for the selection range on the track bar control.
`property SelStart: Integer; [rw]` |  | Starting value for the selection range on the track bar control.
`property ShowSelRange: Boolean; [rw]` |  | Enables or disables a highlighted selection range with tick marks using the values in SelStart and SelEnd.
`property TabStop: Boolean;` |  | Enables or disables navigation using the Tab key.
`property TickMarks: TTickMark; [rw]` |  | Position for the tick marks relative to the slider in the track bar.
`property TickStyle: TTickStyle; [rw]` |  | Indicates the tick mark drawing style for the control.
`property OnChange: TNotifyEvent; [rw]` |  | Event handler signalled when the Position in the control has been changed.
`end;`

## Inheritance

`TCustomTrackBar` |  | TCustomTrackBar - the base class for TTrackBar.
`TWinControl` |  | Implements a windowed control which can contain other child controls.
`TControl` |  | The base class for visible controls.
`TLCLComponent` |  | The base class for LCL components which have an associated widget.
`TComponent`
?
`TObject`

## Description

TCustomTrackBar defines many of the properties inherited by TTrackBar, a device that allows the user to determine the value of a variable using a quasi-analog slider.