TComponent class

In unit Classes

Base class for all components that need owner-owned functionality.

Declaration

pascal

TComponent = class(TPersistent)

Inheritance

TComponent
TPersistent
TObject

Descends from it: TBaseMediator TBaseSingleInstance TBasicAction TBuildEngine TCustomApplication TCustomConnection TCustomDaemonMapper TCustomInstaller TCustomLazComponentQueue TCustomPropertyStorage TCustomSession TCustomSQLStatement TCustomTimer TDaemonController TDataModule TDataSet TDataSource TDBLookup TDBTransaction TDictionary TDragManager TEventLog TExprBuiltInManager TField TFileVersionInfo TFPCustomHTTPClient TFPCustomTimer TFPExpressionParser TFPMimeTypes THelpDatabase THelpViewer THTTPContentProducer THTTPRouter TIPCBase TJSONApplier TJSONToPascal TLCLComponent TPascalCodeGenerator TPopupNotifier TProcess TSessionFactory TSimpleIPC TWebHandler TXMLConfig

Description

TComponent is the base class for any set of classes that needs owner-owned functionality, and which needs support for property streaming. All classes that should be handled by an IDE (Integrated Development Environment) must descend from TComponent, as it includes all support for streaming all its published properties.

Components can 'own' other components. TComponent introduces methods for enumerating the child components. It also allows to name the owned components with a unique name. Furthermore, functionality for sending notifications when a component is removed from the list or removed from memory altogether is also introduced in TComponent

TComponent introduces a form of automatic memory management: When a component is destroyed, all its child components will be destroyed first.

Properties

`ComObject`	public	Interface reference implemented by the component.
`Components`	public	Indexed list (zero-based) of all owned components.
`ComponentCount`	public	Count of owned components.
`ComponentIndex`	public	Index of component in it's owner's list.
`ComponentState`	public	Current component's state.
`ComponentStyle`	public	Current component's style.
`DesignInfo`	public	Information for IDE designer.
`Owner`	public	Owner of this component.
`VCLComObject`	public	Not implemented.
`Observers`	public
`Name`	published	Name of the component.
`Tag`	published	Tag value of the component.

Methods

`GetObservers`	protected
`CanObserve`	protected
`ObserverAdded`	protected
`GetDeltaStreams`	protected
`ReadDeltaStream`	protected
`ReadDeltaState`	protected
`ChangeName`	protected	Actually sets the component name.
`DefineProperties`	protected	Defines fake top,left properties for handling in the IDE.
`GetChildren`	protected	Must be overridden by descendants to return all child components that must be streamed.
`GetChildOwner`	protected	Returns the owner of any children.
`GetChildParent`	protected	Returns the parent of any children.
`GetOwner`	protected	Returns the owner of this component.
`Loaded`	protected	Called when the component has finished loading.
`Loading`	protected
`Notification`	protected	Called by components that are freed and which received a FreeNotification.
`PaletteCreated`	protected
`ReadState`	protected	Read the component's state from a stream.
`RemoveFreeNotifications`	protected
`SetAncestor`	protected	Sets the csAncestor state of the component.
`SetDesigning`	protected	Sets the csDesigning state of the component.
`SetDesignInstance`	protected
`SetInline`	protected
`SetName`	protected	Write handler for Name property.
`SetChildOrder`	protected	Determines the order in which children are streamed/created.
`SetParentComponent`	protected	Set the parent component.
`Updating`	protected	Sets the state to csUpdating.
`Updated`	protected	Ends the csUpdating state.
`UpdateRegistry`	protected	For compatibility only.
`ValidateRename`	protected	Called when a name change must be validated.
`ValidateContainer`	protected	??
`ValidateInsert`	protected	Called when an insert must be validated.
`QueryInterface`	protected
`_AddRef`	protected
`_Release`	protected
`iicrGetComponent`	protected
`GetTypeInfoCount`	protected
`GetTypeInfo`	protected
`GetIDsOfNames`	protected
`Invoke`	protected
`WriteState`	public	Writes the component to a stream.
`Create`	public	Creates a new instance of the component.
`Destroy`	public	Destroys the instance of the component.
`BeforeDestruction`	public	Overrides standard BeforeDestruction.
`DestroyComponents`	public	Destroy child components.
`Destroying`	public	Called when the component is being destroyed.
`ExecuteAction`	public	Standard action execution method.
`FindComponent`	public	Finds and returns the named component in the owned components.
`FreeNotification`	public	Ask the component to notify called when it is being destroyed.
`RemoveFreeNotification`	public	Remove a component from the Free Notification list.
`FreeOnRelease`	public	Part of the IVCLComObject interface.
`GetEnumerator`	public	Create an IEnumerator instance.
`GetNamePath`	public	Returns the name path of this component.
`GetParentComponent`	public	Returns the parent component.
`HasParent`	public	Does the component have a parent ?
`InsertComponent`	public	Insert the given component in the list of owned components.
`RemoveComponent`	public	Remove the given component from the list of owned components.
`SafeCallException`	public	Part of the IVCLComObject Interface.
`SetSubComponent`	public	Sets the csSubComponent style.
`UpdateAction`	public	Updates the state of an action.
`IsImplementorOf`	public	Checks if the current component is the implementor of the interface.
`ReferenceInterface`	public	Interface implementation of Notification.
`ToString`	public	Return a string representation for the object.

Events

OnGetDeltaStreams public

Fields

`FComponentStyle`	protected	Contains the component's style.
`ToStringNameMode`	public

Types and constants

TToStringNameMode public

Inherited

From TPersistent (5)

Assign AssignTo FPOAttachObserver FPODetachObserver FPONotifyObservers

From TObject (37)

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

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