TControl class

In unit Controls

The base class for visible controls.

Declaration

pascal

TControl = class(TLCLComponent)

Inheritance

TControl
TLCLComponent
TComponent

Descends from it: TGraphicControl TWinControl

Description

TControl is a TLCLComponent descendant which implements the base class for visual controls in the LCL ( Lazarus Component Library). TControl extends ancestor classes, like TLCLComponent and TComponent, with properties and methods needed to configure the appearance and behavior for the visual control and handle user interactions at run-time.

Some properties and methods are in all of its descendent classes. Others are implemented as needed in descendent classes. The properties and methods fall into categories like:

Appearance
Position and Orientation
Sizing and Aligning
Assistance and Accessibility
Drag and Drop
Docking
Action Support
Hi-DPI Awareness and Scaling
Handler Lists for Event Notifications
Window and Control Message Handling
Keyboard and Mouse Message Handling
Widgetset-specific Members and Methods

Applications do not normally create instances of TControl. It is used as an ancestor for descendent classes which implement additional features or behaviors.

TControl does not provide a window handle needed to draw the control in the underlying widgetset class. It includes a Parent property which is the windowed control where the control is hosted. It also provides the handle needed to draw the control.

Use TWinControl for a control which provides its own window handle.

Properties

`AutoSizing`	protected	Contains True while auto-sizing is in progress.
`AutoSizingAll`	protected	Flag to prevent recursive AutoSizing (in DoAllAutoSize).
`AutoSizingLockCount`	protected	Internal counter increased and decreased in the DisableAutoSizing and EnableAutoSizing methods.
`ActionLink`	protected	Link to the default Action associated with this control.
`DesktopFont`	protected	Indicates if the desktop (system) font is used for the text displayed on this control.
`DragCursor`	protected	The cursor shape shown during a drag operation.
`DragKind`	protected	Indicates the action performed for a drag operation: drag-and-drop or drag-and-dock.
`DragMode`	protected	Determines how a drag operation is started for the control.
`MouseCapture`	protected	True when mouse messages are currently captured by this control.
`ParentBackground`	protected	Indicates if the control uses the background color from its Parent control.
`ParentColor`	protected	Use the Color from the Parent control, when enabled.
`ParentFont`	protected	Indicates if the Font from the Parent control is used in the control.
`ParentShowHint`	protected	If True, the value of ShowHint for the control will be the same as the one from the Parent. Default is True.
`SessionProperties`	protected	Delimited list of property or sub-component property names saved to and restored from an external storage mechanism.
`Text`	protected	String with the text or caption for the control.
`AnchoredControls`	public	Provides indexed access to controls which are anchored to the current control by their ordinal position.
`BaseBounds`	public	The rectangle with the designed bounds for the control.
`ReadBounds`	public	Reflects the Bounds for the Control read during LCL component streaming.
`BaseParentClientSize`	public	The client size for the Parent, for which the BaseBounds are valid.
`AccessibleName`	public	Contains the accessible name for the control, like the value for its Caption or Name property.
`AccessibleDescription`	public	Provides the accessibility description for the control, like "a text caption", etc.
`AccessibleValue`	public	The accessibility value for the control.
`AccessibleRole`	public	The accessibility role for the control which classifies what kind of object in the class instance.
`Action`	public	The Action associated with the control.
`Align`	public	Specifies the placement of the control on its Parent control.
`Anchors`	public	The set of anchor definitions for this control.
`AnchorSide`	public	Array of anchor definitions, indexed by the control sides.
`AutoSize`	public	Allows automatic adjustment of the size for the control, according to its content.
`BorderSpacing`	public	Determines the inner and outer border spacing for this control.
`BoundsRect`	public	The Top, Left and Bottom, Right for the control, in client coordinates.
`BoundsRectForNewParent`	public	Temporary BoundsRect, used when the control e.g. is docked into a different Parent.
`Caption`	public	The text displayed for the control.
`CaptureMouseButtons`	public	Indicates the mouse button(s) which are captured for the control.
`ClientHeight`	public	The height for the client area on the control.
`ClientOrigin`	public	Screen coordinates of the Top, Left pixel (in the client area) of the control.
`ClientRect`	public	Size of the client area for the control.
`ClientWidth`	public	The width of the client area for the control.
`Color`	public	The background color for the control.
`Constraints`	public	Contains the minimum and maximum Width and Height for the control.
`ControlOrigin`	public	The top, left pixel for the control in screen coordinates.
`ControlState`	public	Contains state flags which indicate whether the control has been clicked, data is being read, or the control is being re-drawn, etc.
`ControlStyle`	public	Contains style flags which control the features or behaviors enabled for the control.
`Enabled`	public	Determines whether the control responds to mouse or keyboard input.
`Font`	public	The font to be used for text display in this control.
`IsControl`	public	Not used in the current LCL implementation.
`MouseInClient`	public	True when the mouse is in the client area for the control.
`Parent`	public	The control within which the control is shown.
`PopupMenu`	public	A context-sensitive menu that pops up when the right mouse button is clicked over this control.
`ShowHint`	public	Enables Hint display for the control.
`Visible`	public	Allows the control, and all of its children, to be displayed or hidden.
`WindowProc`	public	The handler for all messages.
`DockOrientation`	public	How the control is currently docked. (horizontally, vertically, in a notebook, or not at all).
`Floating`	public	Determines whether the control is floating (not part of a form).
`FloatingDockSiteClass`	public	The class for a floating host dock site for this control.
`HostDockSite`	public	The host site (TWinControl) into which this control is docked. Nil if not docked.
`LRDockWidth`	public	The Width when last docked with siblings to the left or right.
`TBDockHeight`	public	The Height when last docked with siblings above or below.
`UndockHeight`	public	Height for the control when undocked.
`UndockWidth`	public	Width for the control when undocked.
`BiDiMode`	public	Indicates whether text controls use in bi-directional reading.
`ParentBiDiMode`	public	Indicates whether the BiDiMode settings in the Parent control are used.
`AnchorSideLeft`	published	Contains anchor alignment information used to position the control with its left edge anchored to another control.
`AnchorSideTop`	published	Contains anchor alignment information used to position the control with its top edge anchored to another control.
`AnchorSideRight`	published	Contains anchor alignment information used to position the control with its right edge anchored to another control.
`AnchorSideBottom`	published	Contains anchor alignment information used to position the control with its bottom edge anchored to another control.
`Cursor`	published	Contains the shape for the mouse pointer when the mouse is over the control.
`Left`	published	The client coordinate with the left edge for the control.
`Height`	published	The vertical size for the control.
`Hint`	published	The text to show in the Hint window for the control.
`Top`	published	The client coordinate for the top edge of the control.
`Width`	published	The horizontal size for the control.
`HelpType`	published	Indicates whether context-sensitive Help is selected by numeric ID or keyword.
`HelpKeyword`	published	The context-sensitive Help keyword for the control.
`HelpContext`	published	The numeric context-sensitive Help identifier for the control.

Methods

`WSRegisterClass`	protected	Registers this component class with the current WidgetSet.
`GetCursor`	protected	Gets the value for the Cursor property.
`SetCursor`	protected	Sets the value for the Cursor property.
`SetVisible`	protected	Sets the value for the Visible property.
`DoOnParentHandleDestruction`	protected	Performs actions needed when the handle for the parent control is freed.
`DoAutoSize`	protected	For internal use only; call AdjustSize instead.
`DoAllAutoSize`	protected	Resizes and aligns the control and all of it children.
`BeginAutoSizing`	protected	Sets AutoSizing to True; used to prevent loops.
`EndAutoSizing`	protected	End of the auto-sizing process, resets AutoSizing to False.
`AnchorSideChanged`	protected	Request further processing after an anchor side was changed.
`ForeignAnchorSideChanged`	protected	Requests further processing after an anchor side has changed, that anchors another control to this one.
`SetAlign`	protected	Sets the value for the Align property.
`SetAnchors`	protected	Sets the value for the Anchors property.
`SetAutoSize`	protected	Sets the value for the AutoSize property.
`BoundsChanged`	protected	Called when the Bounds of the control have been changed; override as required.
`CreateControlBorderSpacing`	protected	Creates the default BorderSpacing object instance for the class.
`DoConstraintsChange`	protected	Performs actions needed when value(s) in Constraints have been changed.
`DoBorderSpacingChange`	protected	Performs actions needed when border spacing for the control is changed.
`IsBorderSpacingInnerBorderStored`	protected	Checks for an assigned value in BorderSpacing.InnerBorder.
`IsCaptionStored`	protected	Implements the storage specifier for the Caption property.
`SendMoveSizeMessages`	protected	Sends Move and Size messages through the LCL message paths.
`ConstrainedResize`	protected	Signals the OnConstrainedResize handler.
`CalculatePreferredSize`	protected	Override this method to return the preferred height and width for the control.
`DoOnResize`	protected	Signals OnResize event handlers for the control.
`DoOnChangeBounds`	protected	Signals OnChangeBounds event handlers for the control.
`CheckOnChangeBounds`	protected	Checks for changes and calls DoOnChangeBounds if needed.
`Resize`	protected	Checks for changes and calls DoOnResize if needed.
`RequestAlign`	protected	Asks the parent control to realign all controls that are siblings.
`UpdateAnchorRules`	protected	Update the rules for anchoring the control.
`ChangeBounds`	protected	Sets the bounds (left, top, height, width) and optionally the BaseBounds of the control.
`DoSetBounds`	protected	Internal function used to set the bounds for the control (Left, Top, Height, Width).
`ScaleConstraints`	protected	Scales the minimum and maximum Width and Height.
`ChangeScale`	protected	Applies scaling (multiplier and divider) to the bounds coordinates, constraints, and Font in a control.
`CanAutoSize`	protected	Determines if auto-sizing is possible, and if so, gets the new width and height when enabled.
`SetBiDiMode`	protected	Sets the value for the BiDiMode property.
`SetParentBiDiMode`	protected	Sets the value for the ParentBiDiMode property.
`IsAParentAligning`	protected	Determines if a parent control is involved in the alignment process for the control.
`GetClientOrigin`	protected	Gets the value for the ClientOrigin property.
`GetClientRect`	protected	Gets the value for the ClientRect property.
`GetLogicalClientRect`	protected	Logical client area, can be bigger than the visible client area.
`GetScrolledClientRect`	protected	Get the visible part of the logical client area.
`GetClientScrollOffset`	protected	Returns the offset of the scrolled client area (in a scrolling TWinControl).
`GetControlOrigin`	protected	Gets the value for the ControlOrigin property.
`IsClientHeightStored`	protected	Implements the storage specifier for the ClientHeight property.
`IsClientWidthStored`	protected	Implements the storage specifier for the ClientWidth property.
`WidthIsAnchored`	protected	True when both the control's left and right side are anchored.
`HeightIsAnchored`	protected	True when both the control's top and bottom side are anchored.
`WMCancelMode`	protected	Handles a LM_CANCELMODE message for the control.
`WMContextMenu`	protected	Handles a LM_CONTEXTMENU message for the control.
`WMLButtonDown`	protected	Handles a LM_LBUTTONDOWN (left mouse button down) message for the control.
`WMRButtonDown`	protected	Handles a LM_RBUTTONDOWN (right mouse button down) message for the control.
`WMMButtonDown`	protected	Handles a LM_MBUTTONDOWN (middle mouse button down) message for the control.
`WMXButtonDown`	protected	Handles a LM_XBUTTONDOWN (extra mouse button down) message for the control.
`WMLButtonDBLCLK`	protected	Handles a left mouse button double click message for the control.
`WMRButtonDBLCLK`	protected	Message handler for right mouse button double click events.
`WMMButtonDBLCLK`	protected	Message handler for middle mouse button double click events.
`WMXButtonDBLCLK`	protected	Message handler for extra mouse button double click events.
`WMLButtonTripleCLK`	protected	Message handler for left mouse button triple click events.
`WMRButtonTripleCLK`	protected	Message handler for right mouse button triple click events.
`WMMButtonTripleCLK`	protected	Message handler for middle mouse button triple click events.
`WMXButtonTripleCLK`	protected	Message handler for extra mouse button triple click events.
`WMLButtonQuadCLK`	protected	Message handler for left mouse button quadruple click events.
`WMRButtonQuadCLK`	protected	Message handler for right mouse button quadruple click events.
`WMMButtonQuadCLK`	protected	Message handler for middle mouse button quadruple click events.
`WMXButtonQuadCLK`	protected	Message handler for extra mouse button quadruple click events.
`WMMouseMove`	protected	Message handler for mouse move events.
`WMLButtonUp`	protected	Message handler for left mouse button up events.
`WMRButtonUp`	protected	Message handler for right mouse button up events.
`WMMButtonUp`	protected	Message handler for middle mouse button up events.
`WMXButtonUp`	protected	Message handler for extra mouse button up events.
`WMMouseWheel`	protected	Handles mouse wheel messages for the control.
`WMMouseHWheel`	protected	Handles horizontal mouse wheel messages for the control.
`WMMove`	protected	Message handler for control move events.
`WMSize`	protected	Message handler for changed control size.
`WMWindowPosChanged`	protected	Message handler for changed control position events.
`CMChanged`	protected	Handles CM_CHANGED control messages for the control.
`LMCaptureChanged`	protected	Handles a LM_CaptureChanged message for the control.
`CMBiDiModeChanged`	protected	Handles CM_BIDIMODECHANGED messages for the control.
`CMSysFontChanged`	protected	Handles the CM_SYSFONTCHANGED message for the control.
`CMEnabledChanged`	protected	Handles a CM_ENABLEDCHANGED message for the control.
`CMHitTest`	protected	Handles the CM_HITTEST message for the control.
`CMMouseEnter`	protected	Handles a CM_MOUSEENTER message for the control.
`CMMouseLeave`	protected	Handles a CM_MOUSELEAVE message for the control.
`CMHintShow`	protected	Handles the CM_HINTSHOW message for the control.
`CMParentBiDiModeChanged`	protected	Handles a CM_PARENTBIDIMODECHANGED message for the control.
`CMParentColorChanged`	protected	Handles a CM_PARENTCOLORCHANGED message for the control.
`CMParentFontChanged`	protected	Handles a CM_PARENTFONTCHANGED message for the control.
`CMParentShowHintChanged`	protected	Handles a CM_PARENTSHOWHINTCHANGED message for the control.
`CMVisibleChanged`	protected	Handles a CM_VISIBLECHANGED message for the control.
`CMTextChanged`	protected	Handles a CM_TEXTCHANGED message for the control.
`CMCursorChanged`	protected	Handles the CM_CURSORCHANGED message for the control.
`CalculateDockSizes`	protected	Saves the docked and undocked extent of the control.
`CreateFloatingDockSite`	protected	Create a floating dock site with a client area equal to the given screen coordinates.
`GetDockEdge`	protected	Determines the side to which the dragged control shall be docked.
`GetDragImages`	protected	Get the list of images used when a drag operation is active.
`GetFloating`	protected	Determines whether the control is floating.
`GetFloatingDockSiteClass`	protected	Returns the class for a floating host dock site.
`BeforeDragStart`	protected	Performs actions needed before a drag operation is started for the control.
`BeginAutoDrag`	protected	For internal use: user has started dragging the control.
`DoFloatMsg`	protected	Handler called when the control starts floating.
`DockTrackNoTarget`	protected	Adjust the DockRect for floating state (no drop target under the mouse).
`DoDock`	protected	Adjusts the control position and extent for the new docksite.
`DoDragMsg`	protected	Handler for a drag message, sent by the DragManager to the current target control.
`DoEndDock`	protected	Signals the OnEndDock event handler when the control has been undocked.
`DoEndDrag`	protected	Signals the OnEndDrag event handler.
`DoStartDock`	protected	Signals the OnStartDock event handler.
`DoStartDrag`	protected	Signals the OnStartDrag event handler.
`DragCanceled`	protected	Notifies the control of a cancelled drag operation.
`DragOver`	protected	Called when an object is dragged over this control; Determines whether a drop is acceptable, using the OnDragOver handler.
`PositionDockRect`	protected	Get the DockRect for an possible drop.
`SetDragMode`	protected	Sets the value for the DragMode property.
`GetDefaultDockCaption`	protected	Returns the string for the dock caption, by default the control's Name.
`Click`	protected	Signals OnClick and/or executes the ActionLink when the control has been clicked.
`DblClick`	protected	Signals the OnDblClick event handler (when assigned).
`TripleClick`	protected	Signals the OnTripleClick event handler (when assigned).
`QuadClick`	protected	Signals the OnQuadClick event handler (when assigned).
`GetMousePosFromMessage`	protected	Converts the coordinates in the mouse message from SmallInt to LongInt values.
`DoMouseDown`	protected	Performs actions needed to handle a mouse down event for the control.
`DoMouseUp`	protected	Performs actions needed to handle a mouse up event for the control.
`MouseDown`	protected	Handles a mouse down event for the control.
`MouseMove`	protected	Handler for MouseMove events.
`MouseUp`	protected	Signals the OnMouseUp handler.
`MouseEnter`	protected	Signals the OnMouseEnter event handler (when assigned).
`MouseLeave`	protected	Signals the OnMouseLeave event handler (when assigned).
`DialogChar`	protected	Performs actions needed to handle an accelerator key for the control.
`UpdateMouseCursor`	protected	Changes the cursor shape to the value in the Cursor property.
`Changed`	protected	Performs actions needed when the value for the control has been changed.
`GetPalette`	protected	Override GetPalette to return the handle of a color palette.
`GetParentBackground`	protected	Gets the value for the ParentBackground property.
`ChildClassAllowed`	protected	Returns True if the specified class is allowed for children of this control.
`ReadState`	protected	Updates control flags and reads the data for the component.
`Loaded`	protected	Performs actions needed when LCL component streaming has been completed.
`LoadedAll`	protected	Called when the control and its child controls have been loaded, and their control state is changed.
`DefineProperties`	protected	Defines which non-published properties should be streamed (none here).
`AssignTo`	protected	Implements assignment of the control to an Action object, or calls the inherited method.
`FormEndUpdated`	protected	Called for each control on a form where the update count has reached 0 (zero).
`InvalidateControl`	protected	Requests a repaint of the control.
`FontChanged`	protected	Handles changes to the Font property.
`ControlFontClass`	protected
`ParentFontChanged`	protected	[Delphi compatible] Does nothing here, all work is done in CMParentFontChanged.
`GetAction`	protected	Gets the value for the Action property.
`RealGetText`	protected	Returns the Caption property.
`RealSetText`	protected	Sets the value for the Caption property.
`TextChanged`	protected	Performs actions needed when the value for the Text property has been changed.
`GetCachedText`	protected	Returns the cached Text property (FCaption).
`SetAction`	protected	Sets the value for the Action property.
`SetColor`	protected	Sets the value for the Color property.
`SetEnabled`	protected	Sets the value for the Enabled property.
`SetHint`	protected	Sets the value for the Hint property.
`SetName`	protected	Sets the value for the Name property.
`SetParent`	protected	Sets the value for the Parent property.
`SetParentBackground`	protected	Sets the value for the ParentBackground property.
`SetParentComponent`	protected	Sets the value in the Parent property when the new parent component is a TWinControl instance.
`WndProc`	protected	The general message handler for this control.
`ParentFormHandleInitialized`	protected	Internal handler for activities after a form widget has been created.
`GetMouseCapture`	protected	Gets the value for the MouseCapture property.
`CaptureChanged`	protected	Handler for mouse capture moved to a different control.
`Notification`	protected	Notification handler for insertion or deletion of components.
`CanTab`	protected	Determines whether the Tab key can be used for navigation in the control.
`GetDeviceContext`	protected	Returns a device context handle for the control, from Parent.
`GetEnabled`	protected	Gets the value for the Enabled property.
`GetPopupMenu`	protected	Gets the value for the PopupMenu property.
`DoOnShowHint`	protected	Signals the OnShowHint event handler.
`DoMouseWheel`	protected	Signals the OnMouseWheel handlers, when the mouse wheel has been turned.
`DoMouseWheelDown`	protected	Signals the OnMouseWheelDown handler.
`DoMouseWheelUp`	protected	Signals the OnMouseWheelUp handler.
`DoMouseWheelHorz`	protected	Performs actions needed to handle horizontal mouse wheel events.
`DoMouseWheelLeft`	protected	Signals the OnMouseWheelLeft event handler (when assigned).
`DoMouseWheelRight`	protected	Signals the OnMouseWheelRight event handler.
`VisibleChanging`	protected	Notifies all chtOnVisibleChanging handlers for the control.
`VisibleChanged`	protected	Notifies all chtOnVisibleChanged handlers for the control.
`EnabledChanging`	protected	Notifies all chtOnEnabledChanging handlers for the control.
`EnabledChanged`	protected	Notifies all chtOnEnabledChanged handlers for the control.
`AddHandler`	protected	Adds a notification handler for the specified control handler type.
`RemoveHandler`	protected	Removes a notification handler from the list for the specified handler type.
`DoCallNotifyHandler`	protected	Signals handler routines for the specified control handler type.
`DoCallKeyEventHandler`	protected	Passes key events for the specified type to the handlers added to the control.
`DoCallMouseWheelEventHandler`	protected	Executes assigned mouse wheel events until a handler is found for the event notifications.
`DoContextPopup`	protected	Signals the OnContextPopup handler.
`SetZOrder`	protected	Moves the control in front of or behind all sibling controls.
`GetControlClassDefaultSize`	protected	Returns the default dimensions for new instances of the class.
`ColorIsStored`	protected	Implements the storage specifier for the Color property.
`DoAutoAdjustLayout`	protected	Applies layout changes using the specified policy and scaling proportions to the control.
`DoFixDesignFontPPI`	protected	Applies the design-time PPI and resizes the specified control font.
`DoScaleFontPPI`	protected	Implements the ScaleFontsPPI method for the control.
`GetActionLinkClass`	protected	The default ActionLink class (TControlActionLink).
`ActionChange`	protected	Handler for a changed Action.
`DragDrop`	public	Signals the OnDragDrop handler when a dragged object is dropped onto this control.
`Dock`	public	Moves the control into a new docksite.
`ManualDock`	public	Docks a control programmatically.
`ManualFloat`	public	Undocks the control into a floating dock site.
`ReplaceDockedControl`	public	Replaces a previously docked control.
`Docked`	public	Indicates if the control has a host dock site.
`Dragging`	public	Returns True if the control is being dragged.
`GetAccessibleObject`	public	Returns True if the control is being dragged.
`CreateAccessibleObject`	public	Creates a TLazAccessibleObject instance for this control.
`GetSelectedChildAccessibleObject`	public	Returns the currently selected child accessibility object.
`GetChildAccessibleObjectAtPos`	public	Returns the child accessibility object at the given position for the control.
`ScaleDesignToForm`	public	Scales a size value from the design-time PPI to the run-time PPI for the parent form.
`ScaleFormToDesign`	public	Scales a size value from the run-time PPI for the parent form to the design-time PPI.
`Scale96ToForm`	public	Scales a size value from 96 PPI to the run-time PPI for the Screen.
`ScaleFormTo96`	public	Scales a size value from the PPI for the Parent form (or designer control) to 96 PPI.
`Scale96ToFont`	public	Scales a size value from 96 PPI to the PPI setting for the Font in the control.
`ScaleFontTo96`	public	Scales a size value from the PPI setting in the Font for the control to 96 PPI.
`ScaleScreenToFont`	public	Scales a size value from the PPI setting for the Screen to the PPI setting for the Font in the control.
`ScaleFontToScreen`	public	Scales a size value from the PPI setting for the Font to the PPI setting for the Screen.
`Scale96ToScreen`	public	Scales a size value from 96 PPI to the PPI setting for the Screen.
`ScaleScreenTo96`	public	Scales a size value from the PPI setting for the Screen to 96 PPI.
`AdjustSize`	public	Smart way to DoAutoSize.
`AutoSizePhases`	public	Auto-sizing phases enabled for the control.
`AutoSizeDelayed`	public	Returns True if auto-sizing has been delayed until some other process is complete.
`AutoSizeDelayedReport`	public	Returns a string with a debugging message for delayed auto-size requests.
`AutoSizeDelayedHandle`	public	Returns True if AutoSize should be skipped or delayed because of its handle.
`AnchorToNeighbour`	public	Anchor to Sibling at Side.
`AnchorParallel`	public	Anchor parallel to Sibling, at Side.
`AnchorHorizontalCenterTo`	public	Anchors the horizontal center of the control to the center of the specified sibling.
`AnchorVerticalCenterTo`	public	Anchors the vertical center of the control to the center of the specified Sibling.
`AnchorToCompanion`	public	Anchor to Sibling at Side, with the same extent.
`AnchorSame`	public	Copy Sibling's anchoring for Side.
`AnchorAsAlign`	public	Anchor to the Parent using the Align value for the control.
`AnchorClient`	public	Anchor to Parent's full client area.
`AnchoredControlCount`	public	The number of controls anchored to the current control.
`SetBounds`	public	Sets the bounds (Left, Top, Width, Height) of the control.
`SetInitialBounds`	public	Sets the bounds of the control initially, when it is created.
`SetBoundsKeepBase`	public	Set the bounds, keeping the base values.
`GetPreferredSize`	public	Returns default/preferred height and width, for use in auto-sizing.
`GetCanvasScaleFactor`	public	Gets the scaling factor for the canvas used to render the control.
`GetDefaultWidth`	public	The default width for the control independent of any calculated values like Width and GetPreferredSize.
`GetDefaultHeight`	public	The default height for the control independent of any calculated values like Height and GetPreferredSize.
`GetDefaultColor`	public	Gets the default color for the control.
`GetColorResolvingParent`	public	Returns the color of the control while resolving clDefault and ParentColor.
`GetRGBColorResolvingParent`	public	Returns a RGB value for the color used on the control.
`GetSidePosition`	public	Gets the client coordinate for the specified side.
`CNPreferredSizeChanged`	public	Message handler for preferred size changed.
`InvalidatePreferredSize`	public	Marks the preferred size as invalid for this control and all parents (implies that we will look for another).
`GetAnchorsDependingOnParent`	public	Returns the sides which are anchored to the Parent.
`DisableAutoSizing`	public	Disables automatic sizing; implies that the default size is accepted, or sizing is done manually.
`EnableAutoSizing`	public	Enables automatic sizing for the control.
`UpdateBaseBounds`	public	Updates the base bounds for the control; essential if there has been a lot of resizing.
`WriteLayoutDebugReport`	public	Used for debugging.
`AutoAdjustLayout`	public	Applies an automatic adjustment layout policy to the control.
`ShouldAutoAdjust`	public	Indicates whether the height and/or width for a control can be automatically adjusted.
`FixDesignFontsPPI`	public	Corrects the font size for High-DPI-aware applications.
`ScaleFontsPPI`	public	Resizes a font to the specified Pixels per Inch setting.
`Create`	public	Constructor for the class instance.
`Destroy`	public	Removes the control from its Parent.
`BeforeDestruction`	public	Performs notifications before the control is destroyed.
`EditingDone`	public	Signals the OnEditingDone event handler.
`ExecuteDefaultAction`	public	Called when the Return key is pressed, signifying the default action.
`ExecuteCancelAction`	public	Called when the Escape key is pressed or the Cancel button is clicked.
`BeginDrag`	public	Starts a drag operation for the control (programmatically).
`EndDrag`	public	Ends a drag operation by notifying the drag manager.
`BringToFront`	public	Brings the control in front of other sibling controls.
`HasParent`	public	Returns True if there is a Parent component responsible for streaming.
`GetParentComponent`	public	Returns the value in the Parent property.
`IsParentOf`	public	Determines whether this control is a parent of AControl.
`GetTopParent`	public	Finds the control that is the top-most Parent in the control hierarchy.
`FindSubComponent`	public	Finds the sub-component with the specified name in the Components property.
`IsVisible`	public	Gets the effective visibility for the control and all of its Parent controls.
`IsControlVisible`	public	True if the control is Visible, or is in design mode.
`IsEnabled`	public	Returns True if both the control and all of its Parent controls are Enabled.
`IsParentColor`	public	Provides access to the value in the protected ParentColor property.
`IsParentFont`	public	Provides access to the value in the protected ParentFont property.
`FormIsUpdating`	public	True if the form is being updated.
`IsProcessingPaintMsg`	public	True while painting the control.
`Hide`	public	Hides the control by setting the Visible property to False.
`Refresh`	public	Causes the control to be redrawn.
`Repaint`	public	Immediately redraws the control when visible, bypassing the message queue.
`Invalidate`	public	Causes a delayed Repaint of the control by marking its visible area of the control as invalid.
`CheckChildClassAllowed`	public	Returns True if the class is allowed for child controls.
`CheckNewParent`	public	Checks if this control can become a child of AParent.
`SendToBack`	public	Moves all sibling controls in front of this control.
`SetTempCursor`	public	Changes the cursor shape temporarily, preserving the original
`UpdateRolesForForm`	public	Internal method called by a Form when its DefaultControl or CancelControl has changed.
`ActiveDefaultControlChanged`	public	Notification of a changed active DefaultControl of a form.
`GetTextBuf`	public	Copy the Text property into Buffer.
`GetTextLen`	public	The length of the Text for the control.
`SetTextBuf`	public	Updates the Text property from a PChar buffer.
`Perform`	public	Calls a message handler directly, bypassing the message queue.
`ScreenToClient`	public	Converts absolute screen coordinates into client-relative coordinates.
`ClientToScreen`	public	Converts client-relative coordinates to absolute screen coordinates.
`ScreenToControl`	public	Converts absolute screen coordinates to control-relative coordinates.
`ControlToScreen`	public	Converts control-relative coordinates to absolute screen coordinates.
`ClientToParent`	public	Converts the specified client coordinates to the screen coordinates for the specified parent control.
`ParentToClient`	public	Converts the specified client coordinates on a parent control to the client coordinates for the control instance.
`GetChildrenRect`	public	Get the visible part of a possibly scrolled client area.
`Show`	public	Makes the control visible by setting Visible to True.
`Update`	public	Redraws invalidated parts of the control immediately.
`HandleObjectShouldBeVisible`	public	True if the control should be visible, unless it's being destroyed.
`ParentDestroyingHandle`	public	Returns True if any parent control is destroying its Handle (or handles for its children).
`ParentHandlesAllocated`	public	Returns True if all Parents have allocated handles, and are not being destroyed.
`InitiateAction`	public	Updates the action associated with the control using its action link.
`ShowHelp`	public	Displays the help associated with the control.
`HasHelp`	public	Indicates whether a HelpKeyword or HelpContext identifier is assigned for the control.
`RemoveAllHandlersOfObject`	public	Removes all control handler types for the specified object.
`AddHandlerOnResize`	public	Adds or inserts the specified OnResize event handler.
`RemoveHandlerOnResize`	public	Removes the specified OnResize event handler.
`AddHandlerOnChangeBounds`	public	Adds or inserts the specified OnChangeBounds event handler.
`RemoveHandlerOnChangeBounds`	public	Removes the specified OnChangeBounds event handler.
`AddHandlerOnVisibleChanging`	public	Adds or inserts the specified OnVisibleChanging event handler.
`RemoveHandlerOnVisibleChanging`	public	Removes the specified OnVisibleChanging event handler.
`AddHandlerOnVisibleChanged`	public	Adds or inserts the specified OnVisibleChanged event handler.
`RemoveHandlerOnVisibleChanged`	public	Removes the specified OnVisibleChanged event handler.
`AddHandlerOnEnabledChanging`	public	Adds the specified OnEnabledChanging handler.
`RemoveHandlerOnEnabledChanging`	public	Removes the specified OnEnabledChanging event handler.
`AddHandlerOnEnabledChanged`	public	Adds an OnEnabledChanged handler.
`RemoveHandlerOnEnabledChanged`	public	Removes the specified OnEnabledChanged event handler.
`AddHandlerOnKeyDown`	public	Adds the specified OnKeyDown event handler.
`RemoveHandlerOnKeyDown`	public	Removes the specified OnKeyDown event handler.
`AddHandlerOnBeforeDestruction`	public	Adds or inserts the specified OnBeforeDestruction event handler.
`RemoveHandlerOnBeforeDestruction`	public	Removes the specified OnBeforeDestruction event handler.
`AddHandlerOnMouseWheel`	public	Adds or inserts the specified OnMouseWheel event handler.
`RemoveHandlerOnMouseWheel`	public	Removes the specified OnMouseWheel event handler.
`UseRightToLeftAlignment`	public	True when BiDiMode is bdRightToLeft.
`UseRightToLeftReading`	public	True when BiDiMode is not bdLeftToRight.
`UseRightToLeftScrollBar`	public	True when BiDiMode indicates right-to-left reading is in use.
`IsRightToLeft`	public	True when BiDiMode is not bdLeftToRight.

Events

`OnConstrainedResize`	protected	This handler can supply specific Constraints (size limits), when the control is resized.
`OnContextPopup`	protected	Invoked when a context-sensitive pop-up menu is requested.
`OnDblClick`	protected	Event handler signalled when a mouse double click occurs in the control.
`OnTripleClick`	protected	Event handler signalled when a mouse triple click occurs in the control.
`OnQuadClick`	protected	Event handler signalled when a mouse quadruple mouse occurs in the control.
`OnDragDrop`	protected	Event handler signalled when an object is dropped onto the control.
`OnDragOver`	protected	Event handler signalled when a control is dragged over the control instance.
`OnEndDock`	protected	Event handler signalled for the end of a drag-dock operation.
`OnEndDrag`	protected	Event handler signalled for the end of a drag-drop operation.
`OnMouseDown`	protected	Event handler signalled when a mouse down event is handled for the control.
`OnMouseMove`	protected	Event handler signalled when the mouse pointer is moved in the control.
`OnMouseUp`	protected	Event handler signalled when a mouse up event is handled for the control.
`OnMouseEnter`	protected	Event handler signalled when the mouse pointer has entered the control.
`OnMouseLeave`	protected	Event handler signalled when the mouse pointer has left the control.
`OnMouseWheel`	protected	Event handler for mouse wheel turned.
`OnMouseWheelDown`	protected	Event handler signalled for a downward movement of the mouse wheel.
`OnMouseWheelUp`	protected	Event handler signalled for an upward movement of the mouse wheel.
`OnMouseWheelHorz`	protected	Event handler signalled for a horizontal movement of the mouse wheel.
`OnMouseWheelLeft`	protected	Event handler signalled for a leftward movement of the mouse wheel.
`OnMouseWheelRight`	protected	Event handler signalled for a rightward movement of the mouse wheel.
`OnStartDock`	protected	Event handler for the start of a docking operation.
`OnStartDrag`	protected	Event handler signalled for the start of a dragging operation.
`OnEditingDone`	protected	Event handler signalled when editing is completed for the control.
`OnChangeBounds`	public	Event handler signalled when the Bounds for the control have been changed.
`OnClick`	public	Notification handler for mouse clicks.
`OnResize`	public	Notification handler for a resize of the control.
`OnShowHint`	public	Event handler signalled when a hint window is displayed for the control.

Fields

`FAccessibleObject`	protected	Member with the accessibility object for the control.
`FControlState`	protected	Member with the value for the ControlState property.
`FCursor`	protected	Member with the value for the Cursor property.
`FCompStyle`	public	Enables use of the 'IN' operator for component styles.

Inherited

From TLCLComponent (6)

DecLCLRefCount GetWSComponentClass IncLCLRefCount LCLRefCount NewInstance WidgetSetClass

An experiment, built from Lazarus main 2dfa93c66e of 10-22-2026. Not the official Lazarus documentation.