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The base type for TForm classes.
Source position: forms.pp line 520
type TCustomForm = class(TCustomDesignControl) |
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protected |
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procedure WMActivate(); message; |
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Handles the LM_ACTIVATE message which activates or deactivates the form. |
procedure WMCloseQuery(); message; |
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Handles the LM_CLOSEQUERY message used to close the window. |
procedure WMHelp(); message; |
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Handles the LM_HELP window message for the form. |
procedure WMShowWindow(); message; |
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Handles the LM_SHOWWINDOW window message for the form. |
procedure WMSize(); message; |
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Handles the LM_SIZE window message for the form. |
procedure WMWindowPosChanging(); message; |
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Notifies the magnetic window manager when the position for a form is being updated. |
procedure WMWindowPosChanged(); message; |
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Handles the LM_WINDOWPOSCHANGED window message for the form. |
procedure CMBiDiModeChanged(); message; |
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Handles the CM_BIDIMODECHANGED control message for the form. |
procedure CMParentBiDiModeChanged(); message; |
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Handles the CM_PARENTBIDIMODECHANGED control message for the form. |
procedure CMAppShowBtnGlyphChanged(); message; |
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Handles the CM_APPSHOWBTNGLYPHCHANGED control message for the form. |
procedure CMAppShowMenuGlyphChanged(); message; |
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Handles the CM_APPSHOWMENUGLYPHCHANGED control message for the form. |
procedure CMIconChanged(); message; |
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Handles the CM_ICONCHANGED control message for the form. |
procedure CMRelease(); message; |
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Handles the CM_RELEASE control message for the form. |
procedure CMActivate(); message; |
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Handles the CM_ACTIVATE control message for the form. |
procedure CMDeactivate(); message; |
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Handles the CM_DEACTIVATE control message for the form. |
procedure CMShowingChanged(); message; |
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Handles the CM_SHOWINGCHANGED control message for the form. |
procedure WMDPIChanged(); message; |
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Handles the LM_DPICHANGED window message for the form. |
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Member used to store the action lists associated with the form. |
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The border style affects the title bar, border and resize behavior of the form. |
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State flags for the form. |
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class procedure WSRegisterClass; override; |
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Registers this component class with the current WidgetSet. |
procedure DoShowWindow; virtual; |
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Chooses the active control when the form becomes visible at run-time. |
procedure Activate; virtual; |
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Notifies the OnActivate event handler. |
procedure ActiveChanged; virtual; |
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An empty implementation in TCustomForm. |
procedure AdjustClientRect(); override; |
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Excludes borders from the given rectangle. |
procedure BeginFormUpdate; |
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Increments the form update counter, and disables auto-sizing on the initial update lock. |
function ColorIsStored; override; |
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Implements the storage specifier for the Color property. |
procedure CreateParams(); override; |
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Initializes parameters used to create the handle for the form instance. |
procedure CreateWnd; override; |
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Creates the handle for the widgetset class and updates it Menu and Icons. |
procedure Deactivate; virtual; |
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Performs actions when the form loses focus. |
procedure DoClose(); virtual; |
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Notifies handlers of the close action for the form. |
procedure DoCreate; virtual; |
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Notifies the create handlers for the form instance. |
procedure DoDestroy; virtual; |
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Signals the OnDestroy event handler for the form instance. |
procedure DoHide; virtual; |
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Signals the OnHide event handler for the form instance. |
procedure DoShow; virtual; |
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Signals the OnShow event handler when needed. |
procedure EndFormUpdate; |
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Decrements the form update counter, and re-enables auto-sizing on the form. |
function HandleCreateException; virtual; |
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Indicates if an exception in the OnCreate event handler is handled by the application. |
function HandleDestroyException; virtual; |
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Placeholder for exception handlers in derived classes. |
function HandleShowHideException; virtual; |
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Placeholder for exception handlers in derived classes. |
procedure InitializeWnd; override; |
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Initializes the widget, also for AlphaBlend and AllowDropFiles. |
procedure Loaded; override; |
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Performs actions when the component has been loaded using the LCL streaming mechanism. |
procedure ChildHandlesCreated; override; |
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Called when handles for child control are created in the form instance. |
procedure Notification(); override; |
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Handles the notification when a component is added to or removed from the form. |
procedure PaintWindow(); override; |
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Calls the Paint method using the specified device context in the control Canvas. |
procedure RequestAlign; override; |
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Calls the user Alignment handler (AlignControls). Here: NOP for a top-level form. |
procedure Resizing(); override; |
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Performs actions needed when the form processes the WMSize message. |
procedure CalculatePreferredSize(); override; |
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Calculates the clipping width and height for a top-level form on the monitor WorkArea. |
procedure DoOnResize; override; |
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Performs a delayed resize action using the DelayedEvent for the control. |
procedure DoOnChangeBounds; override; |
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Performs a delayed bounds change using the DelayedEvent for the control. |
procedure SetZOrder(); override; |
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Moves a top-level form in front of or behind all other forms. |
procedure SetParent(); override; |
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Sets the value for the Parent property. |
procedure MoveToDefaultPosition; virtual; |
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Moves the form to the location specified in the Position property. |
procedure UpdateShowing; override; |
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Configures and position the form when its visibility has been changed. |
procedure SetVisible(); override; |
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Sets the value for the Visible property. |
procedure AllAutoSized; override; |
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If the form is about to show, calculate its metrics. |
procedure DoFirstShow; virtual; |
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Executes handlers using the FirstShow handler type. |
procedure UpdateWindowState; |
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UpdateWindowState is an empty implementation in TCustomForm. |
procedure VisibleChanging; override; |
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Notifies all VisibleChanging handlers. |
procedure VisibleChanged; override; |
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Notifies all handlers when the visibility for the form has been changed. |
procedure WndProc(); override; |
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The general message handler for this control. |
function VisibleIsStored; |
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Implements the storage specifier for the Visible property. |
procedure DoAutoSize; override; |
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For internal use only; call AdjustSize instead. |
procedure SetAutoSize(); override; |
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Sets the value for the AutoSize property. |
procedure SetAutoScroll(); override; |
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Sets the value for the AutoScroll property. |
procedure SetScaled(); override; |
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Sets the value for the Scaled property. |
procedure DoAddActionList(); |
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Adds the specified list of actions to the ActionList for the form. |
procedure DoRemoveActionList(); |
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Removes the specified list of actions from the internal list. |
procedure ProcessResource; virtual; |
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Loads resources needed for the form. |
procedure BeginAutoDrag; override; |
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Re-implements the auto-drag behavior for forms. |
procedure DoDock(); override; |
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Docks or undocks the form in the specified dock site. |
function GetFloating; override; |
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Gets the value for the Floating properties. |
function GetDefaultDockCaption; override; |
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Default caption displayed when the form is docked. |
procedure CMActionExecute(); message; |
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Handles the CM_ACTIONEXECUTE control message. |
procedure CMActionUpdate(); message; |
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Handles the CM_ACTIONUPDATE control message. |
function DoExecuteAction(); |
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Asks all applicable components to execute an action. |
function DoUpdateAction(); |
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Tries all applicable components to update an action. |
procedure UpdateActions; virtual; |
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Asks all components on the form to update their actions. |
property ClientHandle: HWND; [r] |
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The Handle of the MDIForm client (container for MDI children). |
public |
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constructor Create(); override; |
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Constructor for the class instance. |
constructor CreateNew(); virtual; |
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Creates a form instance without a resource (.lfm) file. |
destructor Destroy; override; |
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Destructor for the class instance. |
procedure AfterConstruction; override; |
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Performs actions when the form has been created and loaded from its resource file. |
procedure BeforeDestruction; override; |
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Performs actions before the form instance is physically freed. |
class function GetControlClassDefaultSize; override; |
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Returns the default dimensions for new instances of the class. |
function BigIconHandle; |
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Returns the handle for the large icon on the form or in the application. |
procedure Close; |
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Closes the form. |
function CloseQuery; virtual; |
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Asks the OnCloseQuery handler whether the form can be closed. |
procedure DefocusControl(); |
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Updates ActiveControl if it is to be de-focused. |
procedure DestroyWnd; override; |
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Destroys the interface object (widget). |
procedure EnsureVisible(); |
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Ensures that the form is fully visible, and optionally brings it in front of all other forms. |
procedure FocusControl(); |
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Gives focus to the specified control. |
function FormIsUpdating; override; |
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Indicates if the BeginFormUpdate method has been called without a corresponding EndFormUpdate method call. |
function GetFormImage; |
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Makes a Bitmap image with the Form content. |
function GetRolesForControl(); |
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Gets the role(s) for the control in a modal form (default or cancel button). |
function GetRealPopupParent; |
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Gets the form that is the effective parent for the pop-up, dialog, or splash screen. |
procedure Hide; |
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Hides the control by setting the Visible property to False. |
procedure IntfDropFiles(); |
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Invokes the OnDropFiles handler of the form. This function is called by the LCL interface. |
procedure IntfHelp(); |
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Shows help for a control or menu item. This function is called by the LCL interface. |
function IsShortcut(); virtual; |
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Determines whether the specified message contains a shortcut or accelerator key. |
procedure MakeFullyVisible(); |
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Resizes the form for the specified monitor. |
function AutoSizeDelayedHandle; override; |
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Returns True if an auto-size action should be skipped when a form handle is not available. |
procedure GetPreferredSize(); override; |
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Returns default/preferred height and width, for use in auto-sizing. |
procedure Release; |
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Marks the form for destruction. |
function CanFocus; override; |
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True when the form can receive focus. |
procedure SetFocus; override; |
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Ensures that the control or window handle has focus. |
function SetFocusedControl(); virtual; |
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Handles a focus change for a control (enter/exit messages). |
procedure SetRestoredBounds(); |
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Sets the bounds for the restored control. |
procedure Show; |
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Displays the form instance with support for High DPI scaling. |
function ShowModal; virtual; |
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Displays the form as a modal dialog. |
procedure ShowOnTop; |
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Displays the form in front of all other forms. |
function SmallIconHandle; |
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Returns (and optionally creates) the Handle for the small Icon used for the form. |
procedure GetChildren(); override; |
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Executes the specified callback for all child Controls, and Components with no Parent. |
function WantChildKey(); virtual; |
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Indicates if key messages in a child control are handled in the message processing loop for the form. |
procedure RemoveAllHandlersOfObject(); override; |
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Override this method to remove all references to notification handlers in AnObject. |
procedure AddHandlerFirstShow(); |
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Adds a handler routine called the first time the form is shown. |
procedure RemoveHandlerFirstShow(); |
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Removes the handler called the first time the form executes its Show method. |
procedure AddHandlerClose(); |
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Adds a handler for a form close event. |
procedure RemoveHandlerClose(); |
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Removes a form close handler added to the form instance. |
procedure AddHandlerCreate(); |
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Adds a handler for a form create event. |
procedure RemoveHandlerCreate(); |
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Removes a form create handler added to the form instance. |
function ActiveMDIChild; virtual; |
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Returns the currently active MDI child form. |
function GetMDIChildren(); virtual; |
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Provides indexed access to MDI child forms when used as a MDI form. |
function MDIChildCount; virtual; |
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Provides indexed access to MDI child forms when used as a MDI form. |
procedure AutoScale; |
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Sets scaled to True and calls AutoAdjustLayout with the current PPI for the monitor. |
procedure Dock(); override; |
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Docks the form to the specified dock site. |
procedure UpdateDockCaption(); override; |
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Gets the combined Caption for DockClients on the form. |
property Active: Boolean; [r] |
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Indicates if the form is enabled, visible, and has focus. |
property ActiveControl: TWinControl; [rw] |
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Specifies the active control on the form. |
property ActiveDefaultControl: TControl; [rw] |
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Specifies the active default control on the form. |
property AllowDropFiles: Boolean; [rw] |
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Specifies whether files can be dropped onto this form. |
property AlphaBlend: Boolean; [rw] |
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Allows the form to be drawn with translucency. |
property AlphaBlendValue: Byte; [rw] |
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The translucence level for the form (0=transparent, 255=opaque). |
property AutoScroll: Boolean; [s] |
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Indicates if the form can automatically show or hide scroll bars. |
property BorderIcons: TBorderIcons; [rw] |
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Specifies the icons which appear in the title bar for the form. |
property BorderStyle: TFormBorderStyle; [rw] |
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The border style affects the title bar, border and resize behavior of the form. |
property CancelControl: TControl; [rw] |
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The control associated with the Cancel action. |
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The text displayed in the title bar for the form. |
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The background color for the form. |
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property DefaultControl: TControl; [rw] |
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The control associated with the default action for this form. |
property DefaultMonitor: TDefaultMonitor; [rw] |
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The monitor on which the form is displayed. |
property Designer: TIDesigner; [rw] |
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The designer object when the form is in design mode. |
property EffectiveShowInTaskBar: TShowInTaskbar; [r] |
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Value for the ShowInTaskBar property when resolved using the Application settings. |
property FormState: TFormState; [r] |
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State flags for the form. |
property FormStyle: TFormStyle; [rw] |
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Indicates the style for the form. |
property HelpFile: string; [rw] |
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The name of the help file for the form. |
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The Icon associated with this Form (in minimized state). |
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property KeyPreview: Boolean; [rw] |
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Allows the form to intercept keystrokes in child controls. |
property MDIChildren []: TCustomForm; [r] |
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Provides indexed access to MDI child forms when used as a MDI form. |
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The main menu for the form instance. |
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property ModalResult: TModalResult; [rw] |
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Specifies the return value for a form (or dialog) displayed modally. |
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Contains the Monitor where the form is shown. |
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property LastActiveControl: TWinControl; [r] |
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Tracks focus changes for the active form or the last active control on the current form. |
property PopupMode: TPopupMode; [rw] |
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Defines where pop-up menus are shown. |
property PopupParent: TCustomForm; [rw] |
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Parent form which owns the current form instance when displayed as a pop-up window. |
property SnapOptions: TWindowMagnetOptions; [rw] |
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Contains the form and screen snapping options for the form instance. |
property ScreenSnap: Boolean; [rws] |
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Indicates whether the form instance can be snapped to an edge on the monitor. |
property SnapBuffer: Integer; [rws] |
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Distance from (or proximity to) an edge on a snap target where the snapping behavior is automatically engaged. |
property OnActivate: TNotifyEvent; [rw] |
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Handler called when the form receives focus. |
property OnClose: TCloseEvent; [rws] |
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Handler called when the form is closed. It determines what happens to the form (destroy, hide, etc.). |
property OnCloseQuery: TCloseQueryEvent; [rws] |
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Event handler signalled when trying to close a form. |
property OnCreate: TNotifyEvent; [rw] |
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Handler called when the form has been created. |
property OnDeactivate: TNotifyEvent; [rw] |
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Handler called when the form is deactivated (loses focus). |
property OnDestroy: TNotifyEvent; [rw] |
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Handler called when the form is destroyed. |
property OnDropFiles: TDropFilesEvent; [rw] |
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Handler called when files have been dropped. |
property OnHelp: THelpEvent; [rw] |
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Handler called when Help is requested. |
property OnHide: TNotifyEvent; [rw] |
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Handler called when the form is being hidden. |
property OnResize: TNotifyEvent; [s] |
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Event handler signalled when the size for the form is changed. |
property OnShortcut: TShortCutEvent; [rw] |
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Event handler signalled when a key is pressed, before further handling of the key. |
property OnShow: TNotifyEvent; [rw] |
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Handler called when the form becomes visible. |
property OnShowModalFinished: TModalDialogFinished; [rw] |
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Event handler signalled when modal display of the form has been completed. |
property OnWindowStateChange: TNotifyEvent; [rw] |
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Handler called when the form is minimized, maximized or restored. |
property ParentFont: Boolean; |
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Uses the font from the Parent when enabled. |
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The initial placement for the form. |
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property RestoredLeft: Integer; [r] |
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The Left coordinate for the form when it is restored (i.e. changes from minimized or maximized). |
property RestoredTop: Integer; [r] |
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The Top coordinate for the form when it is restored (i.e. changes from minimized or maximized). |
property RestoredWidth: Integer; [r] |
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The width of the form when it is resized. |
property RestoredHeight: Integer; [r] |
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The height of the form when it is resized. |
property ShowInTaskBar: TShowInTaskbar; [rw] |
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Indicates if the form should be displayed on the system Task Bar. |
property Visible: Boolean; [s] |
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Indicates if the control is visible on its parent. |
property WindowState: TWindowState; [rw] |
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Indicates whether the form is displayed in a minimized, maximized, full-screen or normal state. |
end; |
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The base type for TForm classes. |
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Provides a designer surface for scaling and layout of its child controls. |
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Implements a windowed control with scroll bars. |
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The base class for windowed controls which paint themselves. |
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Implements a windowed control which can contain other child controls. |
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The base class for visible controls. |
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The base class for LCL components which have an associated widget. |
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TCustomForm is a TCustomDesignControl descendant that implements the base type for TForm classes.
Forms represent a window or a dialog used as the user interface for a GUI application. It is a container where visual components (such as buttons, labels, edit fields, images, etc.) can be placed. It is also a designer surface which provides design-time support for configuration and layout of the content placed on the form.
TCustomForm acts an abstraction layer which masks implementation-specific routines required for the various widgetsets supported in the Lazarus Component Library (LCL). Methods and properties are provided which interact with the underlying Operating System or platform, and provide a common API for form-related operations.
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Implements a form used in an LCL application. |
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Provides a designer surface for scaling and layout of its child controls. |
Version 3.2 | Generated 2024-02-25 | Home |