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TCustomScrollBar class

In unit StdCtrls

The base class for TScrollBar.

Declaration

pascal

TCustomScrollBar = class(TWinControl)

Inheritance

Descends from it: TScrollBar

Description

TCustomScrollBar is a TWinControl descendant which defines the base class for a scrollbar, such as TScrollBar. TCustomScrollBar can be used for horizontal or vertical scrollbars displayed on a form or scrolling window control.

A scrollbar allows the content in a client area to be scrolled when it extends beyond the window bounds. TCustomScrollBar provides the properties, methods, and events needed to interface with the widgetset class for the platform or operating system.

Use the Kind property to specify the orientation for the scrollbar.

Use Min, Max, SmallChange, LargeChange, PageSize and Position properties to control the scrolling behavior for the scrollbar.

Use the OnChange and OnScroll event handlers to respond to programmatic changes to the scrollbar, or messages received from the widgetset class.

See TControlScrollBar for information about scrollbars used for windowed controls.

See also

Properties

`Kind`	public	Contains the scrollbar orientation, horizontal or vertical.
`LargeChange`	public	The distance to scroll on an click beneath the slider.
`Max`	public	The maximum value for the bottom or right position depending on orientation.
`Min`	public	The minimum value for the top or left position depending on orientation.
`PageSize`	public	The size of the slider relative to the total scroll range.
`Position`	public	The position of the slider in the scrollbar.
`SmallChange`	public	The distance to scroll when the up or down button is clicked.
`TabStop`	public	Enables keyboard navigation using the Tab or Shift+Tab keys.

Methods

`WSRegisterClass`	protected	Registers the widgetset class created for new instances of the control.
`GetControlClassDefaultSize`	protected	Gets the default size for new instances of the class.
`CreateParams`	protected	Initializes the creation parameters for the class instance.
`CreateWnd`	protected	CreateWnd - calls inherited CreateWnd then initializes various Scroll Info properties.
`Change`	protected	Invokes the OnChange event handler for the control.
`Scroll`	protected	Signals the OnScroll event handler.
`CalculatePreferredSize`	protected	Gets the preferred size for new instances of the class.
`Create`	public	Constructor for the class instance.
`SetParams`	public	Updates the Min and Max values, the size of the page, and the position in the scrollbar.

Events

`OnChange`	public	Event handler signalled when the value in Position, Min, Max, or PageSize is changed.
`OnScroll`	public	Event handler signalled when scrollbar messages are applied.

Inherited

From TWinControl (240)

AddControl AdjustClientRect AlignControls AllAutoSized AutoAdjustLayout AutoSizeDelayed AutoSizeDelayedHandle AutoSizeDelayedReport AutoSizePhases BeginUpdateBounds BorderStyle BorderWidth BoundsLockCount BroadCast Brush BrushCreated CachedClientHeight CachedClientWidth CanFocus CanSetFocus CanTab ChangeScale ChildClassAllowed ChildHandlesCreated ChildKey ChildSizing ClientRectNeedsInterfaceUpdate CMBiDiModeChanged CMBorderChanged CMDoubleBufferedChanged CMEnabledChanged CMEnter CMExit CMParentDoubleBufferedChanged CMShowHintChanged CMShowingChanged CMVisibleChanged CNChar CNKeyDown CNKeyUp CNSysKeyDown CNSysKeyUp ContainsControl ControlAtPos ControlCount ControlKeyDown ControlKeyUp Controls ControlsAligned CreateBrush CreateDockManager CreateHandle CreateParented CreateParentedControl CreateSubClass CustomAlignInsertBefore CustomAlignPosition DefaultHandler DefWndProc DesignerDeleting Destroy DestroyHandle DestroyWnd DialogChar DisableAlign DoAddDockClient DoAdjustClientRectChange DoAlignChildControls DoAllAutoSize DoAutoSize DoChildSizingChange DockClientCount DockClients DockDrop DockManager DockOver DockSite DoConstraintsChange DoDockClientMsg DoDockOver DoDragMsg DoEnter DoExit DoFlipChildren DoFloatMsg DoGetDockCaption DoKeyDownBeforeInterface DoKeyPress DoKeyUpBeforeInterface DoRemainingKeyDown DoRemainingKeyUp DoRemoveDockClient DoSendBoundsToInterface DoSendShowHideToInterface DoSetBounds DoubleBuffered DoUnDock DoUndockClientMsg DoUTF8KeyPress EnableAlign EndUpdateBounds EraseBackground FinalizeWnd FindChildControl FindNextControl FixDesignFontsPPIWithChildren FixupTabList FlipChildren Focused FontChanged FormEndUpdated GetAdjustedLogicalClientRect GetBorderStyle GetChildren GetChildrenRect GetClientOrigin GetClientRect GetControlIndex GetControlOrigin GetDeviceContext GetDockCaption GetEnumeratorControls GetEnumeratorControlsReverse GetMouseCapture GetParentHandle GetPreferredSizeClientFrame GetSiteInfo GetTabOrderList GetTextLen GetTopParentHandle Handle HandleAllocated HandleNeeded InitializeWnd InsertControl IntfGetDropFilesTarget IntfUTF8KeyPress Invalidate InvalidateBoundsRealized InvalidateClientRectCache InvalidatePreferredChildSizes IsClientHeightStored IsClientWidthStored IsControlMouseMsg IsFlipped IsResizing IsSpecialSubControl KeyDown KeyDownAfterInterface KeyDownBeforeInterface KeyPress KeyUp KeyUpAfterInterface KeyUpBeforeInterface Loaded LockRealizeBounds MainWndProc NotifyControls OnAlignInsertBefore OnAlignPosition OnDockDrop OnDockOver OnEnter OnExit OnGetDockCaption OnGetSiteInfo OnKeyDown OnKeyPress OnKeyUp OnUnDock OnUTF8KeyPress PaintControls PaintHandler PaintTo PaintWindow ParentDoubleBuffered ParentFormHandleInitialized ParentHandlesAllocated ParentWindow PerformTab RealGetText ReAlign RealizeBounds RealizeBoundsRecursive RealSetText ReloadDockedControl RemoveControl RemoveFocus Repaint ScaleBy ScaleControls ScrollBy ScrollBy_WS SelectFirst SelectNext SendDialogChar SendMoveSizeMessages SetBorderStyle SetBounds SetChildZPosition SetColor SetControlIndex SetDockManager SetFocus SetShape SetTempCursor ShowControl Showing TabOrder UnlockRealizeBounds Update UpdateControlState UpdateDockCaption UpdateShowing UseDockManager UTF8KeyPress VisibleDockClientCount WindowHandle WMChar WMContextMenu WMDestroy WMEnter WMEraseBkgnd WMExit WMKeyDown WMKeyUp WMKillFocus WMMove WMNotify WMPaint WMSetFocus WMShowWindow WMSize WMSysChar WMSysKeyDown WMSysKeyUp WMWindowPosChanged WndProc WriteLayoutDebugReport WSSetText

From TControl (366)

AccessibleDescription AccessibleName AccessibleRole AccessibleValue Action ActionChange ActionLink ActiveDefaultControlChanged AddHandler AddHandlerOnBeforeDestruction AddHandlerOnChangeBounds AddHandlerOnEnabledChanged AddHandlerOnEnabledChanging AddHandlerOnKeyDown AddHandlerOnMouseWheel AddHandlerOnResize AddHandlerOnVisibleChanged AddHandlerOnVisibleChanging AdjustSize Align AnchorAsAlign AnchorClient AnchoredControlCount AnchoredControls AnchorHorizontalCenterTo AnchorParallel Anchors AnchorSame AnchorSide AnchorSideBottom AnchorSideChanged AnchorSideLeft AnchorSideRight AnchorSideTop AnchorToCompanion AnchorToNeighbour AnchorVerticalCenterTo AssignTo AutoSize AutoSizing AutoSizingAll AutoSizingLockCount BaseBounds BaseParentClientSize BeforeDestruction BeforeDragStart BeginAutoDrag BeginAutoSizing BeginDrag BiDiMode BorderSpacing BoundsChanged BoundsRect BoundsRectForNewParent BringToFront CalculateDockSizes CanAutoSize Caption CaptureChanged CaptureMouseButtons ChangeBounds Changed CheckChildClassAllowed CheckNewParent CheckOnChangeBounds Click ClientHeight ClientOrigin ClientRect ClientToParent ClientToScreen ClientWidth CMChanged CMCursorChanged CMHintShow CMHitTest CMMouseEnter CMMouseLeave CMParentBiDiModeChanged CMParentColorChanged CMParentFontChanged CMParentShowHintChanged CMSysFontChanged CMTextChanged CNPreferredSizeChanged Color ColorIsStored ConstrainedResize Constraints ControlFontClass ControlOrigin ControlState ControlStyle ControlToScreen CreateAccessibleObject CreateControlBorderSpacing CreateFloatingDockSite Cursor DblClick DefineProperties DesktopFont DisableAutoSizing DoAutoAdjustLayout DoBorderSpacingChange DoCallKeyEventHandler DoCallMouseWheelEventHandler DoCallNotifyHandler Dock Docked DockOrientation DockTrackNoTarget DoContextPopup DoDock DoEndDock DoEndDrag DoFixDesignFontPPI DoMouseDown DoMouseUp DoMouseWheel DoMouseWheelDown DoMouseWheelHorz DoMouseWheelLeft DoMouseWheelRight DoMouseWheelUp DoOnChangeBounds DoOnParentHandleDestruction DoOnResize DoOnShowHint DoScaleFontPPI DoStartDock DoStartDrag DragCanceled DragCursor DragDrop Dragging DragKind DragMode DragOver EditingDone EnableAutoSizing Enabled EnabledChanged EnabledChanging EndAutoSizing EndDrag ExecuteCancelAction ExecuteDefaultAction FindSubComponent FixDesignFontsPPI Floating FloatingDockSiteClass Font ForeignAnchorSideChanged FormIsUpdating GetAccessibleObject GetAction GetActionLinkClass GetAnchorsDependingOnParent GetCachedText GetCanvasScaleFactor GetChildAccessibleObjectAtPos GetClientScrollOffset GetColorResolvingParent GetCursor GetDefaultColor GetDefaultDockCaption GetDefaultHeight GetDefaultWidth GetDockEdge GetDragImages GetEnabled GetFloating GetFloatingDockSiteClass GetLogicalClientRect GetMousePosFromMessage GetPalette GetParentBackground GetParentComponent GetPopupMenu GetPreferredSize GetRGBColorResolvingParent GetScrolledClientRect GetSelectedChildAccessibleObject GetSidePosition GetTextBuf GetTopParent HandleObjectShouldBeVisible HasHelp HasParent Height HeightIsAnchored HelpContext HelpKeyword HelpType Hide Hint HostDockSite InitiateAction InvalidateControl InvalidatePreferredSize IsAParentAligning IsBorderSpacingInnerBorderStored IsCaptionStored IsControl IsControlVisible IsEnabled IsParentColor IsParentFont IsParentOf IsProcessingPaintMsg IsRightToLeft IsVisible Left LMCaptureChanged LoadedAll LRDockWidth ManualDock ManualFloat MouseCapture MouseDown MouseEnter MouseInClient MouseLeave MouseMove MouseUp Notification OnChangeBounds OnClick OnConstrainedResize OnContextPopup OnDblClick OnDragDrop OnDragOver OnEditingDone OnEndDock OnEndDrag OnMouseDown OnMouseEnter OnMouseLeave OnMouseMove OnMouseUp OnMouseWheel OnMouseWheelDown OnMouseWheelHorz OnMouseWheelLeft OnMouseWheelRight OnMouseWheelUp OnQuadClick OnResize OnShowHint OnStartDock OnStartDrag OnTripleClick Parent ParentBackground ParentBiDiMode ParentColor ParentDestroyingHandle ParentFont ParentFontChanged ParentShowHint ParentToClient Perform PopupMenu PositionDockRect QuadClick ReadBounds ReadState Refresh RemoveAllHandlersOfObject RemoveHandler RemoveHandlerOnBeforeDestruction RemoveHandlerOnChangeBounds RemoveHandlerOnEnabledChanged RemoveHandlerOnEnabledChanging RemoveHandlerOnKeyDown RemoveHandlerOnMouseWheel RemoveHandlerOnResize RemoveHandlerOnVisibleChanged RemoveHandlerOnVisibleChanging ReplaceDockedControl RequestAlign Resize Scale96ToFont Scale96ToForm Scale96ToScreen ScaleConstraints ScaleDesignToForm ScaleFontsPPI ScaleFontTo96 ScaleFontToScreen ScaleFormTo96 ScaleFormToDesign ScaleScreenTo96 ScaleScreenToFont ScreenToClient ScreenToControl SendToBack SessionProperties SetAction SetAlign SetAnchors SetAutoSize SetBiDiMode SetBoundsKeepBase SetCursor SetDragMode SetEnabled SetHint SetInitialBounds SetName SetParent SetParentBackground SetParentBiDiMode SetParentComponent SetTextBuf SetVisible SetZOrder ShouldAutoAdjust Show ShowHelp ShowHint TBDockHeight Text TextChanged Top TripleClick UndockHeight UndockWidth UpdateAnchorRules UpdateBaseBounds UpdateMouseCursor UpdateRolesForForm UseRightToLeftAlignment UseRightToLeftReading UseRightToLeftScrollBar Visible VisibleChanged VisibleChanging Width WidthIsAnchored WindowProc WMCancelMode WMLButtonDBLCLK WMLButtonDown WMLButtonQuadCLK WMLButtonTripleCLK WMLButtonUp WMMButtonDBLCLK WMMButtonDown WMMButtonQuadCLK WMMButtonTripleCLK WMMButtonUp WMMouseHWheel WMMouseMove WMMouseWheel WMRButtonDBLCLK WMRButtonDown WMRButtonQuadCLK WMRButtonTripleCLK WMRButtonUp WMXButtonDBLCLK WMXButtonDown WMXButtonQuadCLK WMXButtonTripleCLK WMXButtonUp

From TLCLComponent (6)

DecLCLRefCount GetWSComponentClass IncLCLRefCount LCLRefCount NewInstance WidgetSetClass

From TComponent (64)

_AddRef _Release CanObserve ChangeName ComObject ComponentCount ComponentIndex Components ComponentState ComponentStyle DesignInfo DestroyComponents Destroying ExecuteAction FindComponent FreeNotification FreeOnRelease GetChildOwner GetChildParent GetDeltaStreams GetEnumerator GetIDsOfNames GetNamePath GetObservers GetOwner GetTypeInfo GetTypeInfoCount iicrGetComponent InsertComponent Invoke IsImplementorOf Loading Name ObserverAdded Observers OnGetDeltaStreams Owner PaletteCreated QueryInterface ReadDeltaState ReadDeltaStream ReferenceInterface RemoveComponent RemoveFreeNotification RemoveFreeNotifications SafeCallException SetAncestor SetChildOrder SetDesigning SetDesignInstance SetInline SetSubComponent Tag ToString TToStringNameMode UpdateAction Updated UpdateRegistry Updating ValidateContainer ValidateInsert ValidateRename VCLComObject WriteState

From TPersistent (4)

Assign FPOAttachObserver FPODetachObserver FPONotifyObservers

From TObject (35)

AfterConstruction CheckDisposed ClassInfo ClassName ClassNameIs ClassParent ClassType CleanupInstance DefaultHandlerStr Dispatch DispatchStr Disposed DisposeOf Equals FieldAddress Free FreeInstance GetDisposed GetHashCode GetInterface GetInterfaceByStr GetInterfaceEntry GetInterfaceEntryByStr GetInterfaceTable GetInterfaceWeak GetLastCastErrorInfo InheritsFrom InitInstance InstanceSize MethodAddress MethodName QualifiedClassName StringMessageTable SystemHasExtendedRTTI UnitName

An experiment, built from development snapshots. Not the official Free Pascal or Lazarus documentation.