控件继承问题--新手（伴水）

Question

这是一个从BitBtn继承的框架，你看看：
unit MyBitBtn;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Buttons;type
  TMyBitBtn = class(TBitBtn)
  private
    { Private declarations }
  protected
    { Protected declarations }
  public
    { Public declarations }
  published
    { Published declarations }
  end;procedure Register;implementationprocedure Register;
begin
  RegisterComponents('Additional', [TMyBitBtn]);
end;end.

Answer 1

//E-Mail: [email protected] DBTreeView;interfaceuses
  Variants, Windows, SysUtils, Messages, Controls, Forms, Classes, ComCtrls,
  Graphics, Menus, StdCtrls, ExtCtrls, Mask, Buttons, DB, DBCtrls, CommCtrl;type
  TDBTreeView = class(TCustomTreeView)
  private
    FDataLink: TFieldDataLink;
    FCanvas: TControlCanvas;
    FFocused: Boolean;
    procedure ActiveChange(Sender: TObject);
    procedure DataChange(Sender: TObject);
    procedure EditingChange(Sender: TObject);
    function GetDataField: string;
    function GetDataSource: TDataSource;
    function GetField: TField;
    function GetReadOnly: Boolean;
    procedure SetDataField(const Value: string);
    procedure SetDataSource(Value: TDataSource);
    procedure SetFocused(Value: Boolean);
    procedure SetReadOnly(Value: Boolean);
    procedure UpdateData(Sender: TObject);
    procedure CMEnter(var Message: TCMEnter); message CM_ENTER;
    procedure CMExit(var Message: TCMExit); message CM_EXIT;
    procedure CMGetDataLink(var Message: TMessage); message CM_GETDATALINK;
  protected
    procedure KeyDown(var Key: Word; Shift: TShiftState); override;
    procedure KeyPress(var Key: Char); override;
    procedure Loaded; override;
    procedure Notification(AComponent: TComponent;
      Operation: TOperation); override;
    procedure Edit(const Item: TTVItem); override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    function ExecuteAction(Action: TBasicAction): Boolean; override;
    function UpdateAction(Action: TBasicAction): Boolean; override;
    property Field: TField read GetField;
  published
    property DataField: string read GetDataField write SetDataField;
    property DataSource: TDataSource read GetDataSource write SetDataSource;
    property ReadOnly: Boolean read GetReadOnly write SetReadOnly default False;
    property Align;
    property Anchors;
    property AutoExpand;
    property BevelEdges;
    property BevelInner;
    property BevelOuter;
    property BevelKind default bkNone;
    property BevelWidth;
    property BiDiMode;
    property BorderStyle;
    property BorderWidth;
    property ChangeDelay;
    property Color;
    property Ctl3D;
    property Constraints;
    property DragKind;
    property DragCursor;
    property DragMode;
    property Enabled;
    property Font;
    property HideSelection;
    property HotTrack;
    property Images;
    property Indent;
    property MultiSelect;
    property MultiSelectStyle;
    property ParentBiDiMode;
    property ParentColor default False;
    property ParentCtl3D;
    property ParentFont;
    property ParentShowHint;
    property PopupMenu;
    property RightClickSelect;
    property RowSelect;
    property ShowButtons;
    property ShowHint;
    property ShowLines;
    property ShowRoot;
    property SortType;
    property StateImages;
    property TabOrder;
    property TabStop default True;
    property ToolTips;
    property Visible;
    property OnAddition;
    property OnAdvancedCustomDraw;
    property OnAdvancedCustomDrawItem;
    property OnChange;
    property OnChanging;
    property OnClick;
    property OnCollapsed;
    property OnCollapsing;
    property OnCompare;
    property OnContextPopup;
    property OnCreateNodeClass;
    property OnCustomDraw;
    property OnCustomDrawItem;
    property OnDblClick;
    property OnDeletion;
    property OnDragDrop;
    property OnDragOver;
    property OnEdited;
    property OnEditing;
    property OnEndDock;
    property OnEndDrag;
    property OnEnter;
    property OnExit;
    property OnExpanding;
    property OnExpanded;
    property OnGetImageIndex;
    property OnGetSelectedIndex;
    property OnKeyDown;
    property OnKeyPress;
    property OnKeyUp;
    property OnMouseDown;
    property OnMouseMove;
    property OnMouseUp;
    property OnStartDock;
    property OnStartDrag;
    { Items must be published after OnGetImageIndex and OnGetSelectedIndex }
    property Items;
  end;procedure Register;implementationprocedure Register;
begin
  RegisterComponents('Zsoft', [TDBTreeView]);
end;{ TDBTreeView }procedure TDBTreeView.ActiveChange(Sender: TObject);
begin
 //
end;procedure TDBTreeView.CMEnter(var Message: TCMEnter);
begin
  SetFocused(True);
  inherited;
  if SysLocale.FarEast and FDataLink.CanModify then
    inherited ReadOnly := False;
end;procedure TDBTreeView.CMExit(var Message: TCMExit);
begin
  try
    FDataLink.UpdateRecord;
  except
    SetFocus;
    raise;
  end;
  SetFocused(False);
  DoExit;
end;procedure TDBTreeView.CMGetDataLink(var Message: TMessage);
begin
  Message.Result := Integer(FDataLink);
end;constructor TDBTreeView.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  inherited ReadOnly := True;
  ControlStyle := ControlStyle + [csReplicatable];
  FDataLink := TFieldDataLink.Create;
  FDataLink.Control := Self;
  FDataLink.OnDataChange := DataChange;
  FDataLink.OnEditingChange := EditingChange;
  FDataLink.OnUpdateData := UpdateData;
  FDataLink.OnActiveChange := ActiveChange;
end;procedure TDBTreeView.DataChange(Sender: TObject);
var
  vStringStream: TStringStream;
begin
  if FDataLink.Field <> nil then begin
    vStringStream := TStringStream.Create(FDataLink.Field.AsString);
    try
      vStringStream.Position := 0;
      LoadFromStream(vStringStream);
    finally
      vStringStream.Free;
    end;
  end;
end;destructor TDBTreeView.Destroy;
begin
  FDataLink.Free;
  FDataLink := nil;
  FCanvas.Free;
  inherited Destroy;
end;procedure TDBTreeView.Edit(const Item: TTVItem);
begin
  FDataLink.Modified;
  inherited Edit(Item);
end;procedure TDBTreeView.EditingChange(Sender: TObject);
begin
  inherited ReadOnly := not FDataLink.Editing;
end;function TDBTreeView.ExecuteAction(Action: TBasicAction): Boolean;
begin
  Result := inherited ExecuteAction(Action) or (FDataLink <> nil) and
    FDataLink.ExecuteAction(Action);
end;function TDBTreeView.GetDataField: string;
begin
  Result := FDataLink.FieldName;
end;function TDBTreeView.GetDataSource: TDataSource;
begin
  Result := FDataLink.DataSource;
end;function TDBTreeView.GetField: TField;
begin
  Result := FDataLink.Field;
end;function TDBTreeView.GetReadOnly: Boolean;
begin
  Result := FDataLink.ReadOnly;
end;procedure TDBTreeView.KeyDown(var Key: Word; Shift: TShiftState);
begin
  inherited KeyDown(Key, Shift);
  if (Key = VK_DELETE) or ((Key = VK_INSERT) and (ssShift in Shift)) then
    FDataLink.Edit;
end;procedure TDBTreeView.KeyPress(var Key: Char);
begin
  inherited KeyPress(Key);
  if (Key in [#32..#255]) and (FDataLink.Field <> nil) and
    not FDataLink.Field.IsValidChar(Key) then
  begin
    MessageBeep(0);
    Key := #0;
  end;
  case Key of
    ^H, ^V, ^X, #32..#255:
      FDataLink.Edit;
    #27:
      begin
        FDataLink.Reset;
        Key := #0;
      end;
  end;
end;procedure TDBTreeView.Loaded;
begin
  inherited Loaded;
  if (csDesigning in ComponentState) then DataChange(Self);
end;procedure TDBTreeView.Notification(AComponent: TComponent;
  Operation: TOperation);
begin
  inherited Notification(AComponent, Operation);
  if (Operation = opRemove) and (FDataLink <> nil) and
    (AComponent = DataSource) then DataSource := nil;
end;procedure TDBTreeView.SetDataField(const Value: string);
begin
  FDataLink.FieldName := Value;
end;procedure TDBTreeView.SetDataSource(Value: TDataSource);
begin
  if not (FDataLink.DataSourceFixed and (csLoading in ComponentState)) then
    FDataLink.DataSource := Value;
  if Value <> nil then Value.FreeNotification(Self);
end;procedure TDBTreeView.SetFocused(Value: Boolean);
begin
  if FFocused <> Value then
  begin
    FFocused := Value;
    FDataLink.Reset;
  end;
end;procedure TDBTreeView.SetReadOnly(Value: Boolean);
begin
  FDataLink.ReadOnly := Value;
  inherited ReadOnly := Value;
end;function TDBTreeView.UpdateAction(Action: TBasicAction): Boolean;
begin
  Result := inherited UpdateAction(Action) or (FDataLink <> nil) and
    FDataLink.UpdateAction(Action);
end;procedure TDBTreeView.UpdateData(Sender: TObject);
var
  vStringStream: TStringStream;
begin
  if FDataLink.Field <> nil then begin
    vStringStream := TStringStream.Create('');
    try
      SaveToStream(vStringStream);
      vStringStream.Position := 0;
      FDataLink.Field.AsString := vStringStream.DataString
    finally
      vStringStream.Free;
    end;
  end;
end;end.

Answer 2

//E-Mail: [email protected] DropFiles;interfaceuses
  Messages, Windows, SysUtils, Controls, Forms, Classes, Menus, Graphics,
  StdCtrls, ShellApi, ComCtrls;type
  TDropFilesEvent = procedure(Sender: TObject; X, Y: Integer; FileNames: TStrings) of object;type
  TDropFilesMemo = class(TCustomMemo)
  private
    FCanDropFiles: Boolean;
    FOnDropFiles: TDropFilesEvent;
    procedure WMDropFiles(var Msg: TMessage); message WM_DROPFILES;
    procedure SetCanDropFiles(const Value: Boolean);
  published
    property Align;
    property Alignment;
    property Anchors;
    property BevelEdges;
    property BevelInner;
    property BevelKind default bkNone;
    property BevelOuter;
    property BiDiMode;
    property BorderStyle;
    property Color;
    property Constraints;
    property Ctl3D;
    property DragCursor;
    property DragKind;
    property DragMode;
    property Enabled;
    property Font;
    property HideSelection;
    property ImeMode;
    property ImeName;
    property Lines;
    property MaxLength;
    property OEMConvert;
    property ParentBiDiMode;
    property ParentColor;
    property ParentCtl3D;
    property ParentFont;
    property ParentShowHint;
    property PopupMenu;
    property ReadOnly;
    property ScrollBars;
    property ShowHint;
    property TabOrder;
    property TabStop;
    property Visible;
    property WantReturns;
    property WantTabs;
    property WordWrap;
    property OnChange;
    property OnClick;
    property OnContextPopup;
    property OnDblClick;
    property OnDragDrop;
    property OnDragOver;
    property OnEndDock;
    property OnEndDrag;
    property OnEnter;
    property OnExit;
    property OnKeyDown;
    property OnKeyPress;
    property OnKeyUp;
    property OnMouseDown;
    property OnMouseMove;
    property OnMouseUp;
    property OnStartDock;
    property OnStartDrag;
    property CanDropFiles: Boolean read FCanDropFiles write SetCanDropFiles;
    property OnDropFiles: TDropFilesEvent read FOnDropFiles write FOnDropFiles;
  end;  TDropFilesEdit = class(TCustomEdit)
  private
    FCanDropFiles: Boolean;
    FOnDropFiles: TDropFilesEvent;
    procedure WMDropFiles(var Msg: TMessage); message WM_DROPFILES;
    procedure SetCanDropFiles(const Value: Boolean);
  published
    property Anchors;
    property AutoSelect;
    property AutoSize;
    property BevelEdges;
    property BevelInner;
    property BevelKind default bkNone;
    property BevelOuter;
    property BiDiMode;
    property BorderStyle;
    property CharCase;
    property Color;
    property Constraints;
    property Ctl3D;
    property DragCursor;
    property DragKind;
    property DragMode;
    property Enabled;
    property Font;
    property HideSelection;
    property ImeMode;
    property ImeName;
    property MaxLength;
    property OEMConvert;
    property ParentBiDiMode;
    property ParentColor;
    property ParentCtl3D;
    property ParentFont;
    property ParentShowHint;
    property PasswordChar;
    property PopupMenu;
    property ReadOnly;
    property ShowHint;
    property TabOrder;
    property TabStop;
    property Text;
    property Visible;
    property OnChange;
    property OnClick;
    property OnContextPopup;
    property OnDblClick;
    property OnDragDrop;
    property OnDragOver;
    property OnEndDock;
    property OnEndDrag;
    property OnEnter;
    property OnExit;
    property OnKeyDown;
    property OnKeyPress;
    property OnKeyUp;
    property OnMouseDown;
    property OnMouseMove;
    property OnMouseUp;
    property OnStartDock;
    property OnStartDrag;
    property CanDropFiles: Boolean read FCanDropFiles write SetCanDropFiles;
    property OnDropFiles: TDropFilesEvent read FOnDropFiles write FOnDropFiles;
  end;  TDropFilesRichEdit = class(TCustomRichEdit)
  private
    FCanDropFiles: Boolean;
    FOnDropFiles: TDropFilesEvent;
    procedure WMDropFiles(var Msg: TMessage); message WM_DROPFILES;
    procedure SetCanDropFiles(const Value: Boolean);
  published
    property Align;
    property Alignment;
    property Anchors;
    property BevelEdges;
    property BevelInner;
    property BevelOuter;
    property BevelKind default bkNone;
    property BevelWidth;
    property BiDiMode;
    property BorderStyle;
    property BorderWidth;
    property Color;
    property Ctl3D;
    property DragCursor;
    property DragKind;
    property DragMode;
    property Enabled;
    property Font;
    property HideSelection;
    property HideScrollBars;
    property ImeMode;
    property ImeName;
    property Constraints;
    property Lines;
    property MaxLength;
    property ParentBiDiMode;
    property ParentColor;
    property ParentCtl3D;
    property ParentFont;
    property ParentShowHint;
    property PlainText;
    property PopupMenu;
    property ReadOnly;
    property ScrollBars;
    property ShowHint;
    property TabOrder;
    property TabStop default True;
    property Visible;
    property WantTabs;
    property WantReturns;
    property WordWrap;
    property OnChange;
    property OnContextPopup;
    property OnDragDrop;
    property OnDragOver;
    property OnEndDock;
    property OnEndDrag;
    property OnEnter;
    property OnExit;
    property OnKeyDown;
    property OnKeyPress;
    property OnKeyUp;
    property OnMouseDown;
    property OnMouseMove;
    property OnMouseUp;
    property OnMouseWheel;
    property OnMouseWheelDown;
    property OnMouseWheelUp;
    property OnProtectChange;
    property OnResizeRequest;
    property OnSaveClipboard;
    property OnSelectionChange;
    property OnStartDock;
    property OnStartDrag;
    property CanDropFiles: Boolean read FCanDropFiles write SetCanDropFiles;
    property OnDropFiles: TDropFilesEvent read FOnDropFiles write FOnDropFiles;
  end;procedure Register;implementationprocedure Register;
begin
  RegisterComponents('Zsoft', [TDropFilesMemo, TDropFilesEdit, TDropFilesRichEdit]);
end;{ TDropFilesMemo }procedure TDropFilesMemo.SetCanDropFiles(const Value: Boolean);
begin
  FCanDropFiles := Value;
  DragAcceptFiles(Handle, FCanDropFiles);
end;procedure TDropFilesMemo.WMDropFiles(var Msg: TMessage);
var
  I, FilesCount: Integer;
  FileName: array[0..MAX_PATH] of Char;
  Point: TPoint;
  FilesNames: TStringList;
begin
  if Assigned(FOnDropFiles) then begin
    FilesNames := TStringList.Create;
    try
      FilesCount := DragQueryFile(THandle(Msg.wParam), Cardinal(-1), nil, 0);
      DragQueryPoint(THandle(Msg.wParam), Point);
      for I := 0 to FilesCount - 1 do begin
        DragQueryFile(THandle(Msg.wParam), I, FileName,
          SizeOf(FileName));
        FilesNames.Add(FileName);
      end;
      FOnDropFiles(Self, Point.X, Point.Y, FilesNames);
    finally
      FilesNames.Free;
    end;
  end;
  Msg.Result := 0;
  DragFinish(THandle(Msg.wParam));
end;{ TDropFilesEdit }procedure TDropFilesEdit.SetCanDropFiles(const Value: Boolean);
begin
  FCanDropFiles := Value;
  DragAcceptFiles(Handle, FCanDropFiles);
end;procedure TDropFilesEdit.WMDropFiles(var Msg: TMessage);
var
  I, FilesCount: Integer;
  FileName: array[0..MAX_PATH] of Char;
  Point: TPoint;
  FilesNames: TStringList;
begin
  if Assigned(FOnDropFiles) then begin
    FilesNames := TStringList.Create;
    try
      FilesCount := DragQueryFile(THandle(Msg.wParam), Cardinal(-1), nil, 0);
      DragQueryPoint(THandle(Msg.wParam), Point);
      for I := 0 to FilesCount - 1 do begin
        DragQueryFile(THandle(Msg.wParam), I, FileName,
          SizeOf(FileName));
        FilesNames.Add(FileName);
      end;
      FOnDropFiles(Self, Point.X, Point.Y, FilesNames);
    finally
      FilesNames.Free;
    end;
  end;
  Msg.Result := 0;
  DragFinish(THandle(Msg.wParam));
end;{ TDropFilesRichEdit }procedure TDropFilesRichEdit.SetCanDropFiles(const Value: Boolean);
begin
  FCanDropFiles := Value;
  DragAcceptFiles(Handle, FCanDropFiles);
end;procedure TDropFilesRichEdit.WMDropFiles(var Msg: TMessage);
var
  I, FilesCount: Integer;
  FileName: array[0..MAX_PATH] of Char;
  Point: TPoint;
  FilesNames: TStringList;
begin
  if Assigned(FOnDropFiles) then begin
    FilesNames := TStringList.Create;
    try
      FilesCount := DragQueryFile(THandle(Msg.wParam), Cardinal(-1), nil, 0);
      DragQueryPoint(THandle(Msg.wParam), Point);
      for I := 0 to FilesCount - 1 do begin
        DragQueryFile(THandle(Msg.wParam), I, FileName,
          SizeOf(FileName));
        FilesNames.Add(FileName);
      end;
      FOnDropFiles(Self, Point.X, Point.Y, FilesNames);
    finally
      FilesNames.Free;
    end;
  end;
  Msg.Result := 0;
  DragFinish(THandle(Msg.wParam));
end;end.

Answer 3

（伴水）你没有开qq吗？,可不可以在qq里谈

Answer 4

呵呵，那就给你一个简单的吧这是一个从TCustomEdit继承下来的控件，显示方式是从右到左（和TEdit相反）
unit EditEx;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;type
  TEditEx = class(TCustomEdit)
  private
    { Private declarations }
  protected
    procedure CreateParams(var Params: TCreateParams); override;
    { Protected declarations  }
  public
    { Public declarations  }
  published
    { Published declarations }
  end;procedure Register;implementation
procedure Register;
begin
  RegisterComponents('Additional', [TEditEx]);
end;{ TEditEx }procedure TEditEx.CreateParams(var Params: TCreateParams);
begin
  inherited;
  Params.Style := Params.Style or ES_RIGHT;
end;end.

Answer 5

//unti2.pas
unit Unit2;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Buttons;type
  TMyBitBtn = class(TBitBtn)
  private
    { Private declarations }
  protected
    { Protected declarations }
  public
    { Public declarations }
    constructor Create(AOwner: TComponent); override;
  published
    { Published declarations }
  end;procedure Register;implementationprocedure Register;
begin
  RegisterComponents('Additional', [TMyBitBtn]);
end;{ TMyBitBtn }constructor TMyBitBtn.Create(AOwner: TComponent);
begin
  inherited;
  Caption := '简单的';
end;end.//unit1.pas
uses Unit2;{$R *.dfm}procedure TForm1.FormCreate(Sender: TObject);
begin
  with TMyBitBtn.Create(Self) do begin
    Parent := Self;
  end;
end;

Answer 6

简单的例子
unit EXNMUDP;interfaceuses
  Windows, Messages, SysUtils, Classes, NMUDP;type
  TEXNMUDP = class(TNMUDP)
  private
    { Private declarations }
  protected
    { Protected declarations }
  public
    function SendText(const S:String):Integer;
    { Public declarations }
  published    { Published declarations }
  end;procedure Register;implementationprocedure Register;
begin
  RegisterComponents('FastNet', [TEXNMUDP]);
end;{ TEXNMUDP }function TEXNMUDP.SendText(const S: String): Integer;
beginend;end.

Answer 7

to Bob7946(X度空间):“制骗大人，好久不见在忙啥？”