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

TTrackBar

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

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

Declaration

Source position: comctrls.pp line 2699

type TTrackBar = class(TCustomTrackBar) end;

published

  property Align: TAlign;

  

Specifies the placement of the control inside its Parent.

  property Anchors: TAnchors;

  

The set of anchor definitions for this control.

  property BorderSpacing: TControlBorderSpacing;

  

Determines the inner and outer border spacing for this control.

  property Color: TColor;

  property Constraints: TSizeConstraints;

  

The minimal and maximal Width and Height of this control.

  property DragCursor: TCursor;

  

The cursor shape shown while the control is dragged.

  property DragMode: TDragMode;

  

Allows the user to drag the control.

  property Enabled: Boolean;

  

Determines whether the control reacts on mouse or keyboard input.

  property Font: TFont;

  property Frequency: Integer;

  

Frequency - how frequently the position of the slider is to be read and updated (currently unsupported)

  property Hint: TTranslateString;

  

The text to show in the Hint window for this control.

  property LineSize: Integer;

  

Line-Size - increment for slider position when an arrow key is pressed

  property Max: Integer;

  

Max - the value corresponding to full movement of the slider. Default = 10

  property Min: Integer;

  

Min - the value associated with the minimum slider position. Default = 0

  property OnChange: TNotifyEvent;

  

OnChange - action to be taken on change in the slider position

  property OnChangeBounds: TNotifyEvent;

  

Event handler for a change of the Bounds of the control.

  property OnClick: TNotifyEvent;

  

Notification handler for mouse clicks.

  property OnContextPopup: TContextPopupEvent;

  

Invoked when a context-sensitive pop-up menu is requested.

  property OnDragDrop: TDragDropEvent;

  

This handler determines the action on an drop onto this control, in a drag-drop operation.

  property OnDragOver: TDragOverEvent;

  

Event handler for a control being dragged over this control.

  property OnEndDrag: TEndDragEvent;

  

Notification handler for the end of a dragging operation.

  property OnEnter: TNotifyEvent;

  

Handler for control receiving the focus.

  property OnExit: TNotifyEvent;

  

Handler for control loosing the focus. This is a good place for checking the finished user input.

  property OnMouseDown: TMouseEvent;

  

Event handler for mouse button going down.

  property OnMouseEnter: TNotifyEvent;

  

Event handler for mouse entering the area of the control.

  property OnMouseLeave: TNotifyEvent;

  

Event handler for mouse leaving the area of the control.

  property OnMouseMove: TMouseMoveEvent;

  

Event handler for mouse movement within the control.

  property OnMouseUp: TMouseEvent;

  

Event handler for mouse button going up.

  property OnMouseWheel: TMouseWheelEvent;

  

Event handler for mouse wheel turned.

  property OnMouseWheelDown: TMouseWheelUpDownEvent;

  

Notification handler for downward movement of mouse wheel.

  property OnMouseWheelUp: TMouseWheelUpDownEvent;

  

Notification handler for upward movement of mouse wheel.

  property OnKeyDown: TKeyEvent;

  

Handler for keyboard key pressed.

  property OnKeyPress: TKeyPressEvent;

  

Handler for a character entered by the user.

  property OnKeyUp: TKeyEvent;

  

Handler for keyboard key released.

  property OnResize: TNotifyEvent;

  

Notification handler for a resize of the control.

  property OnStartDrag: TStartDragEvent;

  

Event handler for the start of a dragging operation.

  property OnUTF8KeyPress: TUTF8KeyPressEvent;

  

Handler for a character entered by the user.

  property Orientation: TTrackBarOrientation;

  

Orientation - horizontal or vertical

  property PageSize: Integer;

  

PageSize - increment for slider position when PageUp or PageDown key is pressed

  property ParentColor: Boolean;

  property ParentFont: Boolean;

  property ParentShowHint: Boolean;

  

If true, the value of ShowHint for the control will be the same as the one from the Parent. Default is true.

  property PopupMenu: TPopupMenu;

  

A context-sensitive menu that pops up when the right mouse button is clicked over this control

  property Position: Integer;

  

Position - the location of the slider along the track bar. Represents the Return value from the control

  property Reversed: Boolean;

  property ScalePos: TTrackBarScalePos;

  

ScalePos - whether scaling label appears at top, bottom, left or right

  property SelEnd: Integer;

  property SelStart: Integer;

  property ShowHint: Boolean;

  

Enables the Hint display.

  property ShowSelRange: Boolean;

  property TabOrder: TTabOrder;

  

Determines the sequence of controls, reachable when the user presses the Tab key.

  property TabStop: Boolean;

  

Allows the user to navigate to this control, by pressing the Tab key.

  property TickMarks: TTickMark;

  

Tickmarks - whether the ticks are above/left, below/right, or both

  property TickStyle: TTickStyle;

  

TickStyle - none, produced automatically or calculated manually

  property Visible: Boolean;

  

Allows to show or hide the control, and all of its children.

Inheritance

TTrackBar

  

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

|

TCustomTrackBar

  

TCustomTrackBar - the base class for TTrackBar

|

TWinControl

  

The base class for controls which can contain other (child) controls.

|

TControl

  

The base class for visible controls.

|

TLCLComponent

  

The base class for LCL components associated with widgets.

|

TComponent

?

TObject

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.

See also

HowToUseStdCtrls

  

How to use StdCtrls, ComCtrls or ExtCtrls

Example

 
procedure TForm1.TrackBar1Change(Sender: TObject);
begin
  ProgressBar1.Position := (TrackBar1.Position)*10
end;
The latest version of this document can be found at lazarus-ccr.sourceforge.net.