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

TControl

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

TControl - the main ancestor class for visual controls.

Declaration

Source position: controls.pp line 826

type TControl = class(TLCLComponent)

protected

  FControlState: TControlState;

  

Flag showing the set of states for this control

  FCursor: TCursor;

  

Flag showing position of cursor

  procedure WSRegisterClass; override;

  

WSRegisterClass - Register this Class for the current Widget Set

  function GetCursor; virtual;

  

Function to find position of the cursor

  procedure SetCursor(); virtual;

  

Procedure to set the position of the cursor

  procedure SetVisible(); virtual;

  

Procedure to set Visible flag and ensure the control can be seen

  procedure DoOnParentHandleDestruction; virtual;

  procedure DoAutoSize; virtual;

  

DoAutoSize - method for actually performing the AutoSize

  procedure BeginAutoSizing;

  

Procedure for the beginning of the autosizing process

  procedure EndAutoSizing;

  

Procedure for the end of the autosizing process

  function AutoSizeCanStart; virtual;

  

AutoSizeCanStart - checks whether DoAutoSize is permitted to start

  procedure AnchorSideChanged(); virtual;

  

Procedure invoked when the anchor side is changed

  procedure ForeignAnchorSideChanged(); virtual;

  

Procedure invoked when the anchor side of a different control (not the current) is changed

  procedure SetAlign(); virtual;

  

Set up the Align rules for this control

  procedure SetAnchors(); virtual;

  

Set the rules for anchoring this control

  procedure SetAutoSize(); virtual;

  

Set the boolean variable that determines whether autosize can function

  procedure BoundsChanged; virtual;

  

Procedure invoked when bounds of the control are changed

  function CreateControlBorderSpacing; virtual;

  

CreateControlBorderSpacing - calls TControlBorderSpacing.Create to create the border spacing for this control

  procedure DoConstraintsChange(); virtual;

  

Procedure to execute a change in the control's constraints

  procedure DoBorderSpacingChange(); virtual;

  

Procedure to execute a change in the control's border spacing

  function IsBorderSpacingInnerBorderStored; virtual;

  

Function to find if details of border spacing are stored

  procedure SendMoveSizeMessages(); virtual;

  

Send a message to the system if the size and/or position of the control change

  procedure ConstrainedResize(); virtual;

  

Procedure for performing a resize within defined boundaries (constraints)

  procedure CalculatePreferredSize(); virtual;

  

CalculatePreferredSize - find default/preferred height and width

  procedure DoOnResize; virtual;

  

Calls OnResize

  procedure DoOnChangeBounds; virtual;

  

Calls the OnChangeBounds event handler

  procedure CheckOnChangeBounds;

  

Checks for changes and calls DoOnChangeBounds

  procedure Resize; virtual;

  

Checks for changes and calls DoOnResize

  procedure RequestAlign; virtual;

  

Smart calling Parent.AlignControls

  procedure UpdateAnchorRules;

  

Update the rules for anchoring the control

  procedure ChangeBounds(); virtual;

  

Procedure for altering the bounds of the control

  procedure DoSetBounds(); virtual;

  

Perform the actual setting of the boundary rectangle

  procedure ChangeScale(); virtual;

  

Change the scale factor (multiplier or divider) for drawing the control

  function CanAutoSize(); virtual;

  

Function to determine if autosizing is possible, and if so, gets the new width and height

  procedure SetAlignedBounds(); virtual;

  

Try to set the automatic changed bounds

  procedure SetBiDiMode(); virtual;

  

SetBiDiMode - specifies the BiDi mode

  procedure SetParentBiDiMode(); virtual;

  

SetParentBiDiMode - specifies the BiDi mode for the parent control

  function IsAParentAligning;

  

Determine if a parent control is involved in the alignment process

  function GetClientOrigin; virtual;

  

Find the origin (top left pixel) of the client control

  function GetClientRect; virtual;

  

Visual size of client area

  function GetLogicalClientRect; virtual;

  

Logical size of client area (e.g. in a TScrollBox the logical client area can be bigger than the visual)

  function GetScrolledClientRect; virtual;

  

Visual client area scrolled

  function GetClientScrollOffset; virtual;

  

Find the offset for scrolling of the client

  function GetControlOrigin; virtual;

  

Find the origin (top left pixel) of this control

  function IsClientHeightStored; virtual;

  

Is Client Height Stored?

  function IsClientWidthStored; virtual;

  

Is Client Width Stored?

  property AutoSizing: Boolean; [r]

  

Is autosizing proceeding?

  property AutoSizingLockCount: Integer; [r]

  procedure WMCancelMode(); message;

  

Protected message to system for CancelMode

  procedure WMContextMenu(); message;

  

Protected messages to system - when context menu is required

  procedure WMLButtonDown(); message;

  

Protected messages to system - when left mouse button is down

  procedure WMRButtonDown(); message;

  

Protected messages to system - when right mouse button is down

  procedure WMMButtonDown(); message;

  

Protected messages to system - when middle button is down

  procedure WMXButtonDown(); message;

  procedure WMLButtonDBLCLK(); message;

  

Protected messages to system - when left button is double-clicked

  procedure WMRButtonDBLCLK(); message;

  

Protected messages to system - when right button is double-clicked

  procedure WMMButtonDBLCLK(); message;

  

Protected messages to system - when middle button is double-clicked

  procedure WMXButtonDBLCLK(); message;

  procedure WMLButtonTripleCLK(); message;

  

Protected messages to system - when left button is triple-clicked

  procedure WMRButtonTripleCLK(); message;

  

Protected messages to system - when right button is triple-clicked

  procedure WMMButtonTripleCLK(); message;

  

Protected messages to system - when middle button is triple-clicked

  procedure WMXButtonTripleCLK(); message;

  procedure WMLButtonQuadCLK(); message;

  

Protected messages to system - when left button is quadruple-clicked

  procedure WMRButtonQuadCLK(); message;

  

Protected messages to system - when right button is quadruple-clicked

  procedure WMMButtonQuadCLK(); message;

  

Protected messages to system - when middle button is quadruple-clicked

  procedure WMXButtonQuadCLK(); message;

  procedure WMMouseMove(); message;

  

Protected messages to system - when mouse cursor has moved

  procedure WMLButtonUp(); message;

  

Protected messages to system - when left button is up

  procedure WMRButtonUp(); message;

  

Protected messages to system - when right button is up

  procedure WMMButtonUp(); message;

  

Protected messages to system - when middle button is up

  procedure WMXButtonUp(); message;

  procedure WMMouseWheel(); message;

  

Protected message to system - when mouse wheel moves

  procedure WMMove(); message;

  

Protected messages to system - when the control is moved

  procedure WMSize(); message;

  

Protected messages to system - when control is sized

  procedure WMWindowPosChanged(); message;

  

Protected messages to system - when window position is changed

  procedure LMCaptureChanged(); message;

  

LCL Message when capture method is changed

  procedure CMBiDiModeChanged(); message;

  

CMBiDiModeChanged - issues control message when BiDi mode is changed

  procedure CMEnabledChanged(); message;

  

Control Message when Enabled status is changed

  procedure CMHitTest(); message;

  

Control Message for Hit Test

  procedure CMMouseEnter(); message;

  

Control Message for entry of mouse

  procedure CMMouseLeave(); message;

  

Control Message for exit of mouse

  procedure CMHintShow(); message;

  

Control message for showing a hint

  procedure CMParentBiDiModeChanged(); message;

  

CMParentBiDiModeChanged - issues a control message when the parent control's BiDi mode is changed

  procedure CMParentColorChanged(); message;

  

Control Message for a change in parent colour

  procedure CMParentShowHintChanged(); message;

  

Control Message for a change in parent hinting status

  procedure CMVisibleChanged(); message;

  

Control Message for a change in visibility

  procedure CMTextChanged(); message;

  

Control Message for a change in the control's text

  procedure CMWantSpecialKey(); message;

  

Control Message when a special key is needed

  procedure CalculateDockSizes;

  

Calculate the sizes required for docking

  function CreateFloatingDockSite();

  

Create a floating dock site within the Bounds specified as an argument

  function GetDockEdge(); virtual;

  

Find out which edge is used for docking (returned in Result)

  function GetDragImages; virtual;

  

Get the list of Images to be dragged - returned as a list

  function GetFloating; virtual;

  

Find out (true or false) whether the control is floating (as opposed to fixed)

  function GetFloatingDockSiteClass; virtual;

  

Returns the class of the floating dock site

  procedure BeginAutoDrag; virtual;

  

Start the AutoDrag process

  procedure DoFloatMsg(); virtual;

  

Sends a message to the operating system about the floating status of ADockSource

  procedure DockTrackNoTarget(); virtual;

  

Track the docking process when no target has been specified

  procedure DoDock(); virtual;

  

Perform the docking manoeuvre to the new dock site at the position specified by ARect

  function DoDragMsg(); virtual;

  

DoDragMsg - sends a drag message at specified position for nominated object and target; returns an integer Result for success

  procedure DoEndDock(); virtual;

  

End the docking process

  procedure DoEndDrag(); virtual;

  

End the dragging process

  procedure DoStartDock(); virtual;

  

Start the docking process

  procedure DoStartDrag(); virtual;

  

DoStartDrag - start performing the drag

  procedure DragCanceled; virtual;

  

DragCanceled - method for signalling that a drag is cancelled

  procedure DragOver(); virtual;

  

Drag the control over the source; Accept determines if the dragged object will be accepted

  procedure PositionDockRect(); virtual;

  

PositionDockRect - place the nominated Drag-Dock object in the Rectangle

  procedure SetDragMode(); virtual;

  

SetDragMode - specify the mode for dragging

  function GetDefaultDockCaption; virtual;

  

GetDefaultDockCaption - returns the default string for dock caption

  procedure Click; virtual;

  

Click - a procedure that allows the programmer to simulate a mouse click over the control, and initiates the same Action as that associated with the OnClick event

  procedure DblClick; virtual;

  

DblClick - a procedure that allows the programmer to simulate a mouse double-click over the control, and initiates the same Action as that associated with the OnDblClick event

  procedure TripleClick; virtual;

  

TripleClick - a procedure that allows the programmer to simulate a mouse triple-click over the control, and initiates the same Action as that associated with the OnTripleClick event

  procedure QuadClick; virtual;

  

QuadClick - a procedure that allows the programmer to simulate a mouse quadruple-click over the control, and initiates the same Action as that associated with the OnQuadClick event

  procedure MouseDown(); virtual;

  

MouseDown - a procedure that allows the programmer to simulate a mouse button being down over the control, and initiates the same Action as that associated with the OnMouseDown event

  procedure MouseMove(); virtual;

  

MouseMove - a procedure that allows the programmer to simulate a mouse being moved over the control, and initiates the same Action as that associated with the OnMouseMove event

  procedure MouseUp(); virtual;

  

MouseUp - a procedure that allows the programmer to simulate a mouse button being Up over the control, and initiates the same Action as that associated with the OnMouseUp event

  procedure MouseEnter; virtual;

  

MouseEnter - a procedure that allows the programmer to simulate a mouse entering the control, and initiates the same Action as that associated with the OnMouseEnter event

  procedure MouseLeave; virtual;

  

MouseLeave - a procedure that allows the programmer to simulate a mouse leaving the control, and initiates the same Action as that associated with the OnMouseLeave event

  function DialogChar(); virtual;

  

DialogChar - a LCL Key Message; returns True if a Dialog character has an associated message

  procedure UpdateMouseCursor();

  

UpdateMouseCursor - ensure co-ordinates X, Y for the cursor are correctly stored

  procedure Changed;

  

Changed - method to signal that a change has occured

  function GetPalette; virtual;

  

GetPalette - returns a handle to the palette for this control

  function ChildClassAllowed(); virtual;

  

ChildClassAllowed - returns True if the specified class is allowed to be a child of this class

  procedure Loaded; override;

  

Loaded - called when the component has finished loading. Calls inherited Loaded then copies various properties from client and parent

  procedure DefineProperties(); override;

  

DefineProperties - declare any properties not specified elsewhere

  procedure AssignTo(); override;

  

AssignTo - if the Destination is a CustomAction, copies some specified properties to the Destination, otherwise calls inherited AssignTo

  procedure FormEndUpdated; virtual;

  

FormEndUpdated - the update for the Form has ended

  procedure InvalidateControl();

  

InvalidateControl - method to render the Control non-valid; visibility and opacity are specified and instructions can be given to ignore Window Controls

  procedure FontChanged(); virtual;

  

FontChanged - method for dealing with a changed font

  procedure ParentFontChanged; virtual;

  

ParentFontChanged - method for dealing with a change in the font of the parent

  function GetAction; virtual;

  

Find the action needed for operation of this control

  function RealGetText; virtual;

  

Function to get a text-string associated with the control

  procedure RealSetText(); virtual;

  

Procedure to store text associated with the control in a string

  procedure TextChanged; virtual;

  

Procedure to deal with changes in text

  function GetCachedText(); virtual;

  

GetCachedText - method for retrieving caption text from cache; returns True if successful

  procedure SetAction(); virtual;

  

Set up the action to be associated with this control

  procedure SetColor(); virtual;

  

Set up the colour to be used by the control

  procedure SetEnabled(); virtual;

  

Set up the flag to determine whether the control is to be enabled

  procedure SetHint(); virtual;

  

Set up the hinting pop-up for this control

  procedure SetName(); override;

  

Set the name of the control

  procedure SetParent(); virtual;

  

Find who the parents are and store the information

  procedure SetParentComponent(); override;

  

SetParentComponent - specify a new component to be the parent

  procedure WndProc(); virtual;

  

WndProc - message handler for the procedure of this window

  procedure ParentFormHandleInitialized; virtual;

  

ParentFormHandleInitialized - called by ChildHandlesCreated of parent form

  procedure CaptureChanged; virtual;

  

CaptureChanged - the method for data capture has changed

  procedure Notification(); override;

  

Notification - calls inherited Notification, then takes action depending on Operation

  function CanTab; virtual;

  

CanTab - if True, the Tab key can be used to navigate to this control

  function GetDeviceContext(); virtual;

  

GetDeviceContext - returns a device handle to correspond with the nominated WindowHandle

  function GetEnabled; virtual;

  

GetEnabled - returns the Enabled status

  function GetPopupMenu; virtual;

  

GetPopupMenu - returns a popup menu for use with this control

  procedure DoOnShowHint();

  

DoOnShowHint - perform the code for the OnShowHint event handler

  function DoMouseWheel(); virtual;

  

DoMouseWheel - performs the action to deal with a movement of the mouse wheel; returns True if handled

  function DoMouseWheelDown(); virtual;

  

DoMouseWheelDown - performs the action for a downward movement of the mouse wheel; returns True if handled

  function DoMouseWheelUp(); virtual;

  

DoMouseWheelUp - performs the action for an upward movement of the mouse wheel; returns True if handled

  procedure VisibleChanging; virtual;

  

VisibleChanging - method to use when the Visible property is changing

  procedure VisibleChanged; virtual;

  

VisibleChanged - method to use when the Visible property has changed

  procedure AddHandler();

  

AddHandler - add a control handler of the nominated type, using the specified method

  procedure RemoveHandler();

  

RemoveHandler - remove a control handler of the nominated type, using the specified method

  procedure DoCallNotifyHandler();

  

DoCallNotifyHandler - calls a Notify Handler of the specified type

  procedure DoContextPopup(); virtual;

  

DoContextPopup - perform the action to display a context-sensitive popup window, at the specified mouse position

  procedure SetZOrder(); virtual;

  

SetZOrder - specify this control's place in the Z-order (ie front-to-back) of controls

  function GetControlClassDefaultSize; virtual;

  

Find the default size for this class of controls (by reference to parents)

  function ColorIsStored; virtual;

  

Returns True if Colour is stored

  function GetActionLinkClass; virtual;

  

GetActionLinkClass - returns the class of the action link

  procedure ActionChange(); virtual;

  

ActionChange - method for changing an action

  property ActionLink: TControlActionLink; [rw]

  

Link to the default action associated with this control

  property DragCursor: TCursor; [rw]

  

DragCursor - the style of cursor to be used during the Drag process

  property DragKind: TDragKind; [rw]

  

DragKind - what sort of dragging? Drag or Dock

  property DragMode: TDragMode; [rw]

  

DragMode - whether manual or automatic

  property MouseCapture: Boolean; [rw]

  

Is the mouse position captured?

  property ParentColor: Boolean; [rw]

  

ParentColor - should the control have the same colour as the parent? Default is true

  property ParentFont: Boolean; [rw]

  

ParentFont - should the control use the same font as the parent? Default is true

  property ParentShowHint: Boolean; [rw]

  

ParentShowHint - does the control adopt the same hinting behaviour as its parent? Default is true

  property SessionProperties: String; [rw]

  

The stored (saved) properties of the current session, expressed as a string

  property Text: TCaption; [rw]

  

Text - the character string in the name or caption of the control

  property OnConstrainedResize: TConstrainedResizeEvent; [rw]

  

Event Handler for constrained resize

  property OnContextPopup: TContextPopupEvent; [rw]

  

Event handler to supply information when a context-sensitive pop-up menu is required

  property OnDblClick: TNotifyEvent; [rw]

  

Event Handle for mouse double-click

  property OnTripleClick: TNotifyEvent; [rw]

  

Event handler for mouse triple-click

  property OnQuadClick: TNotifyEvent; [rw]

  

Event handler for quadruple click

  property OnDragDrop: TDragDropEvent; [rw]

  

Event handler for the Drag-Drop manoeuvre

  property OnDragOver: TDragOverEvent; [rw]

  

Event handler for the case when a control is dragged over another control

  property OnEndDock: TEndDragEvent; [rw]

  

Event handler for the end of a docking manoeuvre

  property OnEndDrag: TEndDragEvent; [rw]

  

Event handler for the end of a dragging process

  property OnMouseDown: TMouseEvent; [rw]

  

Event handler for when a mouse button is pressed down

  property OnMouseMove: TMouseMoveEvent; [rw]

  

Event handler for mouse movement within the current control

  property OnMouseUp: TMouseEvent; [rw]

  

Event handler for when the mouse button is released, ie "up"

  property OnMouseEnter: TNotifyEvent; [rw]

  

Event handler for when the mouse enters the area of the current control

  property OnMouseLeave: TNotifyEvent; [rw]

  

Event handler for when the mouse leaves the area of the current control

  property OnMouseWheel: TMouseWheelEvent; [rw]

  

OnMouseWheel - event handler for a movement of the mouse wheel

  property OnMouseWheelDown: TMouseWheelUpDownEvent; [rw]

  

OnMouseWheelDown - event handler for downward movement of mouse wheel

  property OnMouseWheelUp: TMouseWheelUpDownEvent; [rw]

  

OnMouseWheelUp - event handler for upward movement of mouse wheel

  property OnStartDock: TStartDockEvent; [rw]

  

Event handler for the start of a docking manoeuvre

  property OnStartDrag: TStartDragEvent; [rw]

  

Event handler for start of dragging process

  property OnEditingDone: TNotifyEvent; [rw]

  

Event handler when editing is done

public

  FCompStyle: Byte;

  

FCompStyle - deprecated

  procedure DragDrop(); virtual;

  

DragDrop - Procedure to govern Dragging/Dropping of control

  procedure Dock(); virtual;

  

Dock - Procedure governing Docking of Control

  function ManualDock(); virtual;

  

ManualDock - permits operator-defined docking

  function ManualFloat(); virtual;

  

ManualFloat - the opposite of ManualDock, allows operator to Float a control

  function ReplaceDockedControl();

  

Remove a previously docked control and put a new control in its place

  function Dragging;

  

Returns True if the control is being dragged

  procedure AdjustSize; virtual;

  

AdjustSize - Smart way to DoAutoSize

  function AutoSizeDelayed; virtual;

  

Auto-sizing has been delayed until some other process is complete

  function NeedParentForAutoSize; virtual;

  

NeedParentForAutoSize: True - need to know parent's properties to do autosize. False - can autosize independently

  procedure AnchorToNeighbour();

  

AnchorToNeighbour - anchoring instructions

  procedure AnchorParallel();

  

AnchorParallel - instructions for anchoring beside another control

  procedure AnchorHorizontalCenterTo();

  

AnchorHorizontal - instructions for anchoring

  procedure AnchorVerticalCenterTo();

  

AnchorVertical - instructions for anchoring

  procedure AnchorToCompanion();

  

AnchorToCompanion - anchor to another control, not necessarily an immediate neighbour

  procedure AnchorSame();

  

Anchor on the same side as a sibling

  procedure AnchorAsAlign();

  

AnchorAsAlign - Anchor following same rules as Align

  procedure AnchorClient();

  

Anchor to the client space

  function AnchoredControlCount;

  

The number of controls anchored to this one

  property AnchoredControls: TControl; [r]

  

The indexed list of controls anchored to this one

  procedure SetBounds(); virtual;

  

SetBounds - set the bounds (top. left, height, width) for the window

  procedure SetInitialBounds(); virtual;

  

Sets the bounds of the control initially, when it is created

  procedure SetBoundsKeepBase(); virtual;

  

Set the bounds, keeping the base values

  procedure GetPreferredSize(); virtual;

  

Returns default/preferred height and width, to be used in autosizing algorithms

  function GetDefaultWidth;

  

Find default width (by reference to ancestor)

  function GetDefaultHeight;

  

Find the default height (by reference to ancestor)

  function GetSidePosition();

  

Find which side is being used for anchoring

  procedure CNPreferredSizeChanged;

  

CNPreferredSizeChanged - issue control signal to show that preferrd size has changed

  procedure InvalidatePreferredSize; virtual;

  

Render the preferred size no longer valid (implies that we will look for another)

  function GetAnchorsDependingOnParent();

  

Find out the required anchor settings by reference to the parents

  procedure DisableAutoSizing;

  

Turn off automatic sizing - implies that default is accepted or sizing is done manually

  procedure EnableAutoSizing;

  

Turns on (enables) automatic sizing

  procedure UpdateBaseBounds(); virtual;

  

Update the basic boundaries of the control - essential if there has been a lot of re-sizing

  procedure LockBaseBounds;

  

Lock the base bounds, so that they do not change even if surrounding controls are changed

  procedure UnlockBaseBounds;

  

Unlock the base bounds so that they are free to change as surrounding controls are changed

  property BaseBounds: TRect; [r]

  

The rectangle defining the base bounds for this control

  property ReadBounds: TRect; [r]

  

ReadBounds - find out what bounds have been defined

  procedure WriteLayoutDebugReport(); virtual;

  

Used for debugging

  constructor Create(); override;

  

Create - constructor for TControl and derived classes: calls inherited Create and sets a number of defaults

  destructor Destroy; override;

  

Destroy - Destructor for TControl. Detaches control from parents, removes graphics, frees memory and Operating System handles, pointers etc

  procedure EditingDone; virtual;

  

EditingDone - what to do when you have finished editing; calls the OnEditingDone event handler if assigned

  procedure ExecuteDefaultAction; virtual;

  

What to do when the RETURN button is pressed, signifying default action

  procedure ExecuteCancelAction; virtual;

  

What to do when ESCAPE is hit (or the CANCEL button is selected) - signifying CANCEL

  procedure BeginDrag();

  

BeginDrag - starts the dragging of a control. In this version BringToFront applies

  procedure BringToFront;

  

Bring the control to the front of the viewed screen

  function HasParent; override;

  

HasParent - returns True if there is a parent component responsible for streaming

  function GetParentComponent; override;

  function IsParentOf(); virtual;

  

This control is the parent of another (specified) control

  function GetTopParent;

  

Find which control is the top parent (ie ultimate ancestor)

  function IsVisible; virtual;

  

Returns True if the control is visible on the current desktop

  function IsControlVisible; virtual;

  

Is the control visible on the current desktop?

  function FormIsUpdating; virtual;

  

True if the form is being updated

  procedure Hide;

  

Hide this control

  procedure Refresh;

  

Refresh the data on this control

  procedure Repaint; virtual;

  

Repaint the control, ie refill its canvas

  procedure Invalidate; virtual;

  

Render this control non-valid

  function CheckChildClassAllowed();

  

Function checks whether a particular child class is allowed

  procedure CheckNewParent(); virtual;

  

Checks a new parent for this control

  procedure SendToBack;

  

Send to back, ie place this control behind all other controls in the current screen; it will not be visible unless the controls in front are transparent

  procedure SetTempCursor(); virtual;

  

SetTempCursor - set a temporary cursor

  procedure UpdateRolesForForm; virtual;

  

Update the roles for this form; see whether there have been any changes in its role

  procedure ActiveDefaultControlChanged(); virtual;

  

The active default control has changed to NewControl

  function GetTextBuf(); virtual;

  

Gets text associated with the control from a buffer

  function GetTextLen; virtual;

  

Get the length of the specified text

  procedure SetTextBuf(); virtual;

  

Stores text associated with the control in a buffer

  function Perform();

  

Perform an Action specified by the message and parameters

  function ScreenToClient();

  

Adjust from Screen co-ordinates to Client-relative co-ordinates

  function ClientToScreen();

  

Convert from Client co-ordinates to Screen co-ordinates

  function ScreenToControl();

  

Adjust from Screen co-ordinates to Control-relative co-ordinates

  function ControlToScreen();

  

Convert from control-relative co-ordinates to absolute screen co-ordinates

  function GetChildsRect(); virtual;

  

Gets the rectangular co-ordinates for a child control

  procedure Show;

  

Makes the control visible.

  procedure Update; virtual;

  

Perform the Update method specified by the parent control (if there is one)

  function HandleObjectShouldBeVisible; virtual;

  

HandleObjectShouldBeVisible - returns True if the Handle Object is required to be visible

  function ParentDestroyingHandle;

  

ParentDestroyingHandle - returns True if the parent control is destroying the Handle

  function ParentHandlesAllocated; virtual;

  

ParentHandlesAllocated - returns True if the parent handles have been allocated

  procedure InitiateAction; virtual;

  

InitiateAction - method to start the action associated with this control

  procedure ShowHelp; virtual;

  

Procedure for displaying the Help associated with this control

  function HasHelp;

  

Indicates that this control has an entry in the Help-file

  procedure RemoveAllHandlersOfObject(); override;

  

RemoveAllHandlersOfObject - method for removing all of an object's handlers: part of a clean-up procedure

  procedure AddHandlerOnResize();

  

AddHandlerOnResize - method for adding a handler for the OnResize event

  procedure RemoveHandlerOnResize();

  

RemoveHandlerOnResize - method for removing a handler for the OnResize event

  procedure AddHandlerOnChangeBounds();

  

AddHandlerOnChangeBounds - method for adding a handler for the OnChangeBounds event

  procedure RemoveHandlerOnChangeBounds();

  

RemoveHandlerOnChangeBounds - method to remove a handler for the OnChangeBounds event

  procedure AddHandlerOnVisibleChanging();

  

AddHandlerOnVisibleChanging - method for adding a handler for the OnVisibleChanging event

  procedure RemoveHandlerOnVisibleChanging();

  

RemoveHandlerOnVisibleChanging - method to remove a handler for the OnVisibleChanging event

  procedure AddHandlerOnVisibleChanged();

  

AddHandlerOnVisibleChanged - method for adding a handler for the OnVisibleChanged event

  procedure RemoveHandlerOnVisibleChanged();

  

RemoveHandlerOnVisibleChanged - method to remove handler for the OnVisibleChanged event

  property Action: TBasicAction; [rw]

  

The action to be associated with this control

  property Align: TAlign; [rw]

  

Used to align the control to the top, bottom, left or right of its client.

  property Anchors: TAnchors; [rws]

  

The set of anchor definitions for this control

  property AnchorSide: TAnchorSide; [r]

  

Finds which side to use for anchor

  property AutoSize: Boolean; [rw]

  

Whether auto-size is to be used

  property BorderSpacing: TControlBorderSpacing; [rw]

  

Determines the border spacing for this control

  property BoundsRect: TRect; [rw]

  

Determines the rectangle bounding this control

  property BoundsRectForNewParent: TRect; [rw]

  

BoundsRectForNewParent - finds (or sometimes specifies) the bounding rectangle for a new parent control

  property Caption: TCaption; [rws]

  

Caption - the text-string appearing on the Control, usually used to identify its function

  property CaptureMouseButtons: TCaptureMouseButtons; [rws]

  

Which mouse button(s) to be used for capture? Default left button, but may be a set of up to three

  property ClientHeight: Integer; [rws]

  

ClientHeight - determines the height of the client within which the control exists

  property ClientOrigin: TPoint; [r]

  

ClientOrigin - Top left pixel of the client within which the control exists

  property ClientRect: TRect; [r]

  

ClientRect - finds the position of the rectangle for the client within which the control exists

  property ClientWidth: Integer; [rws]

  

ClientWidth - determines the width of the client within which the control exists

  property Color: TColor; [rws]

  

Determine the colour for the current control

  property Constraints: TSizeConstraints; [rw]

  

Determine Constraints (max and min height and width) for this control

  property ControlOrigin: TPoint; [r]

  

ControlOrigin - top left pixel of this control

  property ControlState: TControlState; [rw]

  

ControlState - whether mouse has been clicked, data being read, control being re-drawn, etc

  property ControlStyle: TControlStyle; [rw]

  

ControlStyle - whether the control responds to mouse clicks, can be re-sized, has particular actions, etc

  property Enabled: Boolean; [rws]

  

Whether the control is Enabled. If not, it usually appears 'greyed-out'

  property Font: TFont; [rws]

  

The Font to be used for text in this control

  property IsControl: Boolean; [rw]

  

Reads or writes a flag to deterine whether this object is actually a control

  property MouseEntered: Boolean; [r]

  

Reads a flag to determine whether the mouse entered the control

  property OnChangeBounds: TNotifyEvent; [rw]

  

Event handler for a change in bounds of the control

  property OnClick: TNotifyEvent; [rws]

  

Event Handler for mouse click

  property OnResize: TNotifyEvent; [rw]

  

Event Handler for resize of control

  property OnShowHint: TControlShowHintEvent; [rw]

  

Event Handler when a hint needs to be shown

  property Parent: TWinControl; [rw]

  

Determine what is the parent for this control

  property PopupMenu: TPopupmenu; [rw]

  

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

  property ShowHint: Boolean; [rws]

  

Flag to determine: Is hint to be displayed for this control?

  property Visible: Boolean; [rws]

  

Visible - can the control be seen?

  property WindowProc: TWndMethod; [rw]

  

Reads or writes a message associated with this window

  property DockOrientation: TDockOrientation; [rw]

  

DockOrientation - whether docking is oriented horizontally, vertically, according to pages or not at all

  property Floating: Boolean; [r]

  

Whether the control is Floating (as opposed to Docked)

  property FloatingDockSiteClass: TWinControlClass; [rw]

  

FloatingDockSiteClass - reads or writes the class of the floating dock site

  property HostDockSite: TWinControl; [rw]

  

HostDockSite - the host site to which this control is docked

  property LRDockWidth: Integer; [rw]

  

LRDockWidth - the docked width from left to right

  property TBDockHeight: Integer; [rw]

  

TBDockHeight - the docked height from top to bottom

  property UndockHeight: Integer; [rw]

  

UndockHeight - the height of the undocked control

  property UndockWidth: Integer; [rw]

  

UnDockWidth - the undocked width of the control

  function UseRightToLeftAlignment; virtual;

  

UseRightToLeftAlignment - as opposed to usual left to right

  function UseRightToLeftReading; virtual;

  

UseRightToLeftReading - as opposed to usual left to right

  function UseRightToLeftScrollBar;

  

UseRightToLeftScrollBar - as opposed to usual left to right

  function IsRightToLeft;

  

IsRightToLeft - as opposed to usual left to right

  property BiDiMode: TBiDiMode; [rws]

  

BiDiMode - enabling bi-directional writing

  property ParentBiDiMode: Boolean; [rw]

  

ParentBiDiMode - does the control follow the BiDiMode settings of its parent?

published

  property AnchorSideLeft: TAnchorSide;

  

Anchor to the left side

  property AnchorSideTop: TAnchorSide;

  

Anchor to the Top

  property AnchorSideRight: TAnchorSide;

  

Anchor to the right side

  property AnchorSideBottom: TAnchorSide;

  

Anchors to the bottom

  property Cursor: TCursor; [rw]

  

The type of cursor to be used with this control

  property Left: Integer; [rw]

  

Left - the coordinate of the left edge of the control

  property Height: Integer; [rw]

  

Height - the vertical dimension of the control

  property Hint: TTranslateString; [rws]

  

Hint - a small informative pop-up box that appears when the mouse 'hovers' over a control

  property Top: Integer; [rw]

  

Top - the coordinates of the top edge of the control

  property Width: Integer; [rw]

  

Width - the horizontal dimension of the control

  property HelpType: THelpType; [rw]

  

The type of help to be used with this control - keyword or context

  property HelpKeyword: String; [rws]

  

The keyword to be used for Help in this control

  property HelpContext: THelpContext; [rws]

  

The context-sensitive help message to be used with this control

end;

Inheritance

TControl

  

TControl - the main ancestor class for visual controls.

|

TLCLComponent

?

TObject

Description

TControl is the main ancestor class for all visual controls.

The definition includes a large number of constants, types and methods that are inherited by derived classes and types.

These include devices for defining and controlling:

Properties defined here can be overridden by descendant classes.

See also

TLCLComponent

  

TLCLComponent - base class for LCL components

TComponent