在尝试使用框架作为组件时,我也遇到了这个问题。解决显而易见的问题有多种可能性,但它们都破坏了信息隐藏的原则(所有框架的子组件都作为已发布的属性公开,这意味着每个人都可以访问它们)。
我通过实现一个通用的“框架控制”组件解决了这个问题:
unit RttiBrow.Cbde.FrameControl;
interface
uses
Classes, Controls, Forms, Messages, ExtCtrls;
type
TFrameClass = class of TFrame;
TComponentFrame = class (TFrame)
private
function GetClientHeight: Integer;
function GetClientWidth: Integer;
procedure SetClientHeight(const Value: Integer);
procedure SetClientWidth(const Value: Integer);
function GetOldCreateOrder: Boolean;
procedure SetOldCreateOrder(const Value: Boolean);
function GetPixelsPerInch: Integer;
procedure SetPixelsPerInch(const Value: Integer);
function GetTextHeight: Integer;
procedure SetTextHeight(const Value: Integer);
published
{ workarounds for IDE bug }
property ClientWidth: Integer read GetClientWidth write SetClientWidth stored False;
property ClientHeight: Integer read GetClientHeight write SetClientHeight stored False;
property OldCreateOrder: Boolean read GetOldCreateOrder write SetOldCreateOrder stored False;
property PixelsPerInch: Integer read GetPixelsPerInch write SetPixelsPerInch stored False;
property TextHeight: Integer read GetTextHeight write SetTextHeight stored False;
end;
TComponentFrame<TFrameControl: class { TControl }> = class (TComponentFrame)
private
function GetController: TFrameControl; inline;
protected
property Controller: TFrameControl read GetController;
public
constructor Create (AOwner: TComponent); override;
end;
TFrameControl<T: TFrame> = class (TWinControl)
private
FFrame: T;
function PlainFrame: TFrame;
protected
procedure CreateParams (var Params: TCreateParams); override;
property Frame: T read FFrame;
public
constructor Create (AOwner: TComponent); override;
property DockManager;
published
property Align;
property Anchors;
property BiDiMode;
property Color;
property Constraints;
property Ctl3D;
property UseDockManager default True;
property DockSite;
property DoubleBuffered;
property DragCursor;
property DragKind;
property DragMode;
property Enabled;
property Font;
property ParentBiDiMode;
property ParentBackground;
property ParentColor;
property ParentCtl3D;
property ParentDoubleBuffered;
property ParentFont;
property ParentShowHint;
property ShowHint;
property TabOrder;
property TabStop;
property Touch;
property Visible;
property OnAlignInsertBefore;
property OnAlignPosition;
property OnCanResize;
property OnConstrainedResize;
property OnDockDrop;
property OnDockOver;
property OnDragDrop;
property OnDragOver;
property OnEndDock;
property OnEndDrag;
property OnEnter;
property OnExit;
property OnGesture;
property OnGetSiteInfo;
property OnMouseActivate;
property OnMouseDown;
property OnMouseEnter;
property OnMouseLeave;
property OnMouseMove;
property OnMouseUp;
property OnResize;
property OnStartDock;
property OnStartDrag;
property OnUnDock;
end;
implementation
uses
Windows;
{ TFrameControl<T> }
constructor TFrameControl<T>.Create(AOwner: TComponent);
begin
inherited;
FFrame := T (TFrameClass (T).Create (Self));
PlainFrame.Parent := Self;
PlainFrame.Align := alClient;
end;
procedure TFrameControl<T>.CreateParams(var Params: TCreateParams);
begin
inherited;
Params.Style := Params.Style or WS_CLIPCHILDREN;
Params.ExStyle := Params.ExStyle or WS_EX_CONTROLPARENT;
end;
function TFrameControl<T>.PlainFrame: TFrame;
begin
Result := FFrame; // buggy compiler workaround
end;
{ TComponentFrame }
function TComponentFrame.GetOldCreateOrder: Boolean;
begin
Result := False;
end;
function TComponentFrame.GetPixelsPerInch: Integer;
begin
Result := 0;
end;
function TComponentFrame.GetTextHeight: Integer;
begin
Result := 0;
end;
procedure TComponentFrame.SetClientHeight(const Value: Integer);
begin
Height := Value;
end;
procedure TComponentFrame.SetClientWidth(const Value: Integer);
begin
Width := Value;
end;
procedure TComponentFrame.SetOldCreateOrder(const Value: Boolean);
begin
end;
procedure TComponentFrame.SetPixelsPerInch(const Value: Integer);
begin
end;
procedure TComponentFrame.SetTextHeight(const Value: Integer);
begin
end;
function TComponentFrame.GetClientHeight: Integer;
begin
Result := Height;
end;
function TComponentFrame.GetClientWidth: Integer;
begin
Result := Width;
end;
{ TComponentFrame<TFrameControl> }
constructor TComponentFrame<TFrameControl>.Create(AOwner: TComponent);
begin
inherited;
Assert (AOwner <> nil);
Assert (AOwner.InheritsFrom (TFrameControl));
end;
function TComponentFrame<TFrameControl>.GetController: TFrameControl;
begin
Result := TFrameControl (Owner);
end;
end.
有了这个类,添加一个框架作为一个组件就变成了一个两阶段的过程:
// frame unit
type
TFilteredList = class;
TFrmFilteredList = class (TComponentFrame<TFilteredList>)
// lots of published sub-components and event methods like this one:
procedure BtnFooClick(Sender: TObject);
end;
TFilteredList = class (TFrameControl<TFrmFilteredList>)
private
procedure Foo;
public
// the component's public interface
published
// the component's published properties
end;
procedure Register;
...
procedure Register;
begin
RegisterComponents ('CBDE Components', [TFilteredList]);
end;
procedure TFrmFilteredList.BtnFooClick(Sender: TObject);
begin
Controller.Foo;
end;
procedure TFilteredList.Foo;
begin
end;
...
使用这种方法时,组件的用户将看不到您的子组件。