TComponent
[Properties (by Name)][Methods (by Name)][Events (by Name)]
Base class for all components that need owner-owned functionality.
Declaration
Source position: classesh.inc line 2044
Type
TComponent = class (TPersistent, IUnknown, IInterfaceComponentReference)
private
FOwner : TComponent;
FName : TComponentName;
FTag : PtrInt;
FComponents : TFPList;
FFreeNotifies : TFPList;
FDesignInfo : LongInt;
FVCLComObject : Pointer;
FComponentState : TComponentState;
function GetComObject : IUnknown;
function GetComponent(AIndex: Integer) : TComponent;
function GetComponentCount : Integer;
function GetComponentIndex : Integer;
procedure Insert(AComponent: TComponent);
procedure ReadLeft(Reader: TReader);
procedure ReadTop(Reader: TReader);
procedure Remove(AComponent: TComponent);
procedure RemoveNotification(AComponent: TComponent);
procedure SetComponentIndex(Value: Integer);
procedure SetReference(Enable: Boolean);
procedure WriteLeft(Writer: TWriter);
procedure WriteTop(Writer: TWriter);
protected
FComponentStyle : TComponentStyle;
procedure ChangeName(const NewName: TComponentName);
procedure DefineProperties(Filer: TFiler); Override;
procedure GetChildren(Proc: TGetChildProc; Root: TComponent); Dynamic;
function GetChildOwner : TComponent; Dynamic;
function GetChildParent : TComponent; Dynamic;
function GetOwner : TPersistent; Override;
procedure Loaded; Virtual;
procedure Loading; Virtual;
procedure Notification(AComponent: TComponent; Operation: TOperation)
; Virtual;
procedure PaletteCreated; Dynamic;
procedure ReadState(Reader: TReader); Virtual;
procedure SetAncestor(Value: Boolean);
procedure SetDesigning(Value: Boolean; SetChildren: Boolean);
procedure SetDesignInstance(Value: Boolean);
procedure SetInline(Value: Boolean);
procedure SetName(const NewName: TComponentName); Virtual;
procedure SetChildOrder(Child: TComponent; Order: Integer); Dynamic;
procedure SetParentComponent(Value: TComponent); Dynamic;
procedure Updating; Dynamic;
procedure Updated; Dynamic;
class procedure UpdateRegistry(Register: Boolean;
const ClassID: string;
const ProgID: string); Dynamic;
procedure ValidateRename(AComponent: TComponent; const CurName: string;
const NewName: string); Virtual;
procedure ValidateContainer(AComponent: TComponent); Dynamic;
procedure ValidateInsert(AComponent: TComponent); Dynamic;
function QueryInterface(const IID: TGuid; out Obj) : HRESULT; Virtual;
function _AddRef : LongInt;
function _Release : LongInt;
function iicrGetComponent : TComponent;
function GetTypeInfoCount(out Count: Integer) : HRESULT;
function GetTypeInfo(Index: Integer; LocaleID: Integer; out TypeInfo)
: HRESULT;
function GetIDsOfNames(const IID: TGuid; Names: Pointer;
NameCount: Integer; LocaleID: Integer;
DispIDs: Pointer) : HRESULT;
function Invoke(DispID: Integer; const IID: TGuid; LocaleID: Integer;
Flags: Word; var Params; VarResult: Pointer;
ExcepInfo: Pointer; ArgErr: Pointer) : HRESULT;
public
procedure WriteState(Writer: TWriter); Virtual;
constructor Create(AOwner: TComponent); Virtual;
destructor Destroy; Override;
procedure BeforeDestruction; Override;
procedure DestroyComponents;
procedure Destroying;
function ExecuteAction(Action: TBasicAction) : Boolean; Dynamic;
function FindComponent(const AName: string) : TComponent;
procedure FreeNotification(AComponent: TComponent);
procedure RemoveFreeNotification(AComponent: TComponent);
procedure FreeOnRelease;
function GetEnumerator : TComponentEnumerator;
function GetNamePath : string; Override;
function GetParentComponent : TComponent; Dynamic;
function HasParent : Boolean; Dynamic;
procedure InsertComponent(AComponent: TComponent);
procedure RemoveComponent(AComponent: TComponent);
function SafeCallException(ExceptObject: TObject;
ExceptAddr: CodePointer) : HRESULT; Override;
procedure SetSubComponent(ASubComponent: Boolean);
function UpdateAction(Action: TBasicAction) : Boolean; Dynamic;
ComObject : IUnknown;
function IsImplementorOf(const Intf: IInterface) : Boolean;
procedure ReferenceInterface(const intf: IInterface; op: TOperation);
Components[Index: Integer]: TComponent;
ComponentCount : Integer;
ComponentIndex : Integer;
ComponentState : TComponentState;
ComponentStyle : TComponentStyle;
DesignInfo : LongInt;
Owner : TComponent;
VCLComObject : Pointer;
published
Name : TComponentName;
Tag : PtrInt;
end
;
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.
Members
| Member | Type | Visibility | Description |
|---|---|---|---|
| BeforeDestruction | Method | public | Overrides standard BeforeDestruction. |
| ChangeName | Method | protected | Actually sets the component name. |
| ComObject | Property | public | Interface reference implemented by the component |
| ComponentCount | Property | public | Count of owned components |
| ComponentIndex | Property | public | Index of component in it's owner's list. |
| Components | Property | public | Indexed list (zero-based) of all owned components. |
| ComponentState | Property | public | Current component's state. |
| ComponentStyle | Property | public | Current component's style. |
| Create | Method | public | Creates a new instance of the component. |
| DefineProperties | Method | protected | Defines fake top,left properties for handling in the IDE. |
| DesignInfo | Property | public | Information for IDE designer. |
| Destroy | Method | public | Destroys the instance of the component. |
| DestroyComponents | Method | public | Destroy child components. |
| Destroying | Method | public | Called when the component is being destroyed |
| ExecuteAction | Method | public | Standard action execution method. |
| FComponents | Field | private | |
| FComponentState | Field | private | |
| FComponentStyle | Field | protected | Contains the component's style. |
| FDesignInfo | Field | private | |
| FFreeNotifies | Field | private | |
| FindComponent | Method | public | Finds and returns the named component in the owned components. |
| FName | Field | private | |
| FOwner | Field | private | |
| FreeNotification | Method | public | Ask the component to notify called when it is being destroyed. |
| FreeOnRelease | Method | public | Part of the IVCLComObject interface. |
| FTag | Field | private | |
| FVCLComObject | Field | private | |
| GetChildOwner | Method | protected | Returns the owner of any children. |
| GetChildParent | Method | protected | Returns the parent of any children. |
| GetChildren | Method | protected | Must be overridden by descendants to return all child components that must be streamed. |
| GetComObject | Method | private | |
| GetComponent | Method | private | |
| GetComponentCount | Method | private | |
| GetComponentIndex | Method | private | |
| GetEnumerator | Method | public | Create an IEnumerator instance |
| GetIDsOfNames | Method | protected | |
| GetNamePath | Method | public | Returns the name path of this component. |
| GetOwner | Method | protected | Returns the owner of this component. |
| GetParentComponent | Method | public | Returns the parent component. |
| GetTypeInfo | Method | protected | |
| GetTypeInfoCount | Method | protected | |
| HasParent | Method | public | Does the component have a parent ? |
| iicrGetComponent | Method | protected | |
| Insert | Method | private | |
| InsertComponent | Method | public | Insert the given component in the list of owned components. |
| Invoke | Method | protected | |
| IsImplementorOf | Method | public | Checks if the current component is the implementor of the interface |
| Loaded | Method | protected | Called when the component has finished loading. |
| Loading | Method | protected | |
| Name | Property | published | Name of the component. |
| Notification | Method | protected | Called by components that are freed and which received a FreeNotification. |
| Owner | Property | public | Owner of this component. |
| PaletteCreated | Method | protected | |
| QueryInterface | Method | protected | |
| ReadLeft | Method | private | |
| ReadState | Method | protected | Read the component's state from a stream. |
| ReadTop | Method | private | |
| ReferenceInterface | Method | public | Interface implementation of Notification |
| Remove | Method | private | |
| RemoveComponent | Method | public | Remove the given component from the list of owned components. |
| RemoveFreeNotification | Method | public | Remove a component from the Free Notification list. |
| RemoveNotification | Method | private | |
| SafeCallException | Method | public | Part of the IVCLComObject Interface. |
| SetAncestor | Method | protected | Sets the csAncestor state of the component. |
| SetChildOrder | Method | protected | Determines the order in which children are streamed/created. |
| SetComponentIndex | Method | private | |
| SetDesigning | Method | protected | Sets the csDesigning state of the component. |
| SetDesignInstance | Method | protected | |
| SetInline | Method | protected | |
| SetName | Method | protected | Write handler for Name property. |
| SetParentComponent | Method | protected | Set the parent component. |
| SetReference | Method | private | |
| SetSubComponent | Method | public | Sets the csSubComponent style. |
| Tag | Property | published | Tag value of the component. |
| UpdateAction | Method | public | Updates the state of an action. |
| Updated | Method | protected | Ends the csUpdating state. |
| UpdateRegistry | Method | protected | For compatibility only. |
| Updating | Method | protected | Sets the state to csUpdating |
| ValidateContainer | Method | protected | ?? |
| ValidateInsert | Method | protected | Called when an insert must be validated. |
| ValidateRename | Method | protected | Called when a name change must be validated |
| VCLComObject | Property | public | Not implemented. |
| WriteLeft | Method | private | |
| WriteState | Method | public | Writes the component to a stream. |
| WriteTop | Method | private | |
| _AddRef | Method | protected | |
| _Release | Method | protected |
Inheritance
| Class | Description |
|---|---|
| TComponent(IUnknown, IInterfaceComponentReference) | Base class for all components that need owner-owned functionality. |