TrackBar

Inheritance Hierarchy

          IComponent

          IControl

          ITrackBar

          TrackBar

Description

The TrackBar component is a control in the form of a slider.

Working with the Component

The slider position can be changed, using the mouse cursor or the keyboard. The current value tracking is performed in the  OnChange event. To manage the slider position, the  Position property is used. Value of the  TickMarks  property is defined by the scale position relative to the component. The  Orientation  property determines the slider orientation. Value of the  TickStyle  property determines the scale representation method.

The  LineSize  and  PageSize  properties define the value of the slider moving when the user moves the slider by the arrow keys or the PAGE UP and the PAGE DOWN keys. properties define the value of the slider moving when the user moves the slider by the arrow keys or the PAGE UP and the PAGE DOWN keys.

By setting the values to the  SelStart  and  SelEnd properties,some range which can be a recommended value range can be visually highlighted. At the same time, nothing prevents the user to move the slider beyond this range.

Example

Properties of the TrackBar Component

  Property name Brief description
Align The Align property determines the behavior of the component, when the size of its parent component is changed.
AllowDrag The AllowDrag property determines whether an object can be dragged from the component.
AllowDrop The AllowDrop property determines whether the component can accept a dragged object.
Anchors The Anchors property returns settings that determine the percentage of the size change for the current component when the parent component is resized.
BorderStyle The BorderStyle property determines the style of a component border.
Brush The Brush property specifies the brush used to fill the component area.
ClientHeight The ClientHeight property is used to receive or specify the height of the component’s client space.
ClientWidth The ClientWidth property is used to receive or specify the width of the component’s client space.
Color The Color property determines the background color of a component.
ComponentCount The ComponentCount property returns the number of child components.
Components The Components property returns the child component.
Cursor The Cursor property determines the look of the cursor over the component.
Data The Data property is used to store any custom data.
Enabled The Enabled property determines whether the component is available for the user.
Focused The Focused property returns True, if the focus is set on the component.
Font The Font property determines the set of characteristics, describing the font, used to display text.
Frequency The Frequency property determines the value used on calculating the number of intervals and location of component area's ticks.
Height The Height property determines the component height.
HelpContext The HelpContext property determines a unique index for the context help section for this component.
Hint The Hint property determines the hint text for the component.
Left The Left property determines the coordinate of the left border of the component.
LineSize The LineSize property determines how much the slider is shifted on clicking arrow buttons.
Max The Max property determines the maximum value of the change range.
Min The Min property determines the minimum value of the change range.
Name The Name property determines the component name.
Orientation The Orientation property determines the control orientation.
PageSize The PageSize property determines how much the slider is shifted on pressing PAGE UP and PAGE DOWN buttons, or on clicking the edge of the scale.
Parent The Parent property determines the parent component.
ParentColor The ParentColor property determines whether the component inherits the color of the parent component.
ParentFont The ParentFont property determines whether the component should use the font of the parent component.
ParentShowHint The ParentShowHint property determines when a tooltip is displayed.
PopupMenu The PopupMenu property determines the context menu to be displayed on right-click.
Position The Position property determines the current slider position.
Scrolls The Scrolls property returns parameters of component's scrollbars.
SelEnd The SelEnd property determines the end selection position.
SelStart The SelStart property determines the start selection position.
ShowHint The ShowHint property enables and disables showing a hint for the component.
SliderVisible The SliderVisible property determines, whether the component slider should be visible.
TabOrder The TabOrder property determines the component position in the tab order.
TabStop The TabStop property determines whether the focus is set to a component when the TAB button is pressed.
Tag The Tag property is not used by the compiler. The user can change the value of the Tag property and use it as required.
Text The Text property determines the row identifying a component for user.
ThumbLength The ThumbLength property determines the slider length.
TickMarks The TickMarks property determines the way the points are indicated.
TickStyle The TickStyle property determines the style of points indication.
Top The Top property determines the coordinate of the top border of the component.
Visible The Visible property determines the visibility of the component during execution.
Width The Width property determines the component width.

Methods of the TrackBar Component

  Method name Brief description
BringToFront The BringToFront method brings a component to front.
ClientToScreen The ClientToScreen method converts point coordinates relative to component coordinates into display coordinates.
DoDragDrop The DoDragDrop method allows to start drag-and-drop operation.
GetImage The GetImage method returns the image of the component with all the child components.
ScreenToClient The ScreenToClient method converts screen coordinates of a point to coordinates specified relative to the component coordinate system.
SendToBack The SendToBack method sends a component to back.
SetFocus The SetFocus method sets focus to this component.
SetTick The SetTick method allows to set a tick in the specified position.

Events of the TrackBar Component

  Event name Brief description
OnBeginDrag The OnBeginDrag event occurs for a component, when a user starts to drag an object from the component.
OnChange The OnChange event occurs when the slider position changes.
OnClick The OnClick event occurs if a user clicks a component area using the main mouse button.
OnDblClick The OnDblClick event occurs if a user double-clicks a component area using the mouse button.
OnDragDrop The OnDragDrop event occurs for a component if a user drops a dragged object over it.
OnDragEnter The OnDragEnter event occurs when a dragged object crosses the borders of this component.
OnDragLeave The OnDragLeave event occurs when a dragged object leaves the borders of this component.
OnDragOver The OnDragOver event occurs for this component when a user drags a dragged object over it.
OnEnter The OnEnter event occurs when a component receives focus.
OnExit The OnExit event occurs when a component loses focus.
OnHScroll The OnHScroll event occurs when the horizontal scrollbar slider changes its position.
OnKeyDown The OnKeyDown event occurs if a component is focused and a keyboard key is pressed.
OnKeyPress The OnKeyPress event occurs if a component is focused when a user presses a character key.
OnKeyPreview The OnKeyPreview event occurs prior to each event requiring clicking.
OnKeyUp The OnKeyUp event occurs if a component is focused and a user releases any button previously pressed.
OnMouseDown The OnMouseDown event occurs when the pointer is in component area and a mouse button is pressed.
OnMouseEnter The OnMouseEnter event occurs when mouse cursor enters the component area.
OnMouseHover The OnMouseHover event occurs when mouse cursor is held in the component area.
OnMouseLeave The OnMouseLeave event occurs when mouse cursor leaves the component area.
OnMouseMove The OnMouseMove event occurs on moving the cursor over component.
OnMouseUp The OnMouseUp event occurs on releasing mouse button when the cursor is in component area.
OnMouseWheel The OnMouseWheel event occurs if the component has focus when the mouse wheel is rotated.
OnVScroll The OnVScroll event occurs when the vertical scrollbar slider changes its position.

See also:

Additional Components