小弟為了下列這一段程式碼，足足奮鬥了十一個小時，始終無法突破，想請大大幫忙看看，下列標了紅字的部分，該如何寫？    

unit UNAV_TOOLBAR;    interface    uses
  ComCtrls, Classes, SysUtils, Dialogs, StdCtrls;    type
  TNavBtn = (nbFirst, nbPrior, nbNext, nbLast, nbInsert, nbDelete, nbEdit, nbPost, nbCancel, nbRefresh);
  TNavBtnSet = set of TNavBtn;      TNavToolBar = class(TToolBar)
  private
    FVisibleButtons: TNavBtnSet;
    procedure SetVisible(Value: TNavBtnSet);
    procedure InitButtons;
  public
    Buttons: array[TNavBtn] of TToolButton;
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
  published
    property VisibleButtons: TNavBtnSet read FVisibleButtons write SetVisible default [nbFirst, nbPrior, nbNext, nbLast, nbInsert, nbDelete, nbEdit, nbPost, nbCancel, nbRefresh];
  end;    procedure Register;    implementation    procedure Register;
begin
  RegisterComponents('APPFII', [TNavToolBar]);
end;    { TNavToolBar }    constructor TNavToolBar.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);      FVisibleButtons := [nbFirst, nbPrior, nbNext, nbLast, nbInsert, nbDelete, nbEdit, nbPost, nbCancel, nbRefresh];      InitButtons;
end;    destructor TNavToolBar.Destroy;
begin
  inherited Destroy;
end;    procedure TNavToolBar.InitButtons;
var
  i: TNavBtn;
  Btn: TToolButton;
begin
  ShowMessage(Self.Name);  //如下圖所示，一片空白      for i := Low(Buttons) to High(Buttons) do
  begin
    Btn := TToolButton.Create(Owner);
    Btn.Parent := Self;  //=>ERROR: Control '' has no parent window.
    Buttons[i] := Btn;
  end;
end;    procedure TNavToolBar.SetVisible(Value: TNavBtnSet);
var
  i: TNavBtn;
begin
  FVisibleButtons := Value;      for i := Low(Buttons) to High(Buttons) do
  begin
    Buttons[i].Visible := i in FVisibleButtons;
    Buttons[i].Enabled := Buttons[i].Visible;
  end;
end;    end.

-------------------------------- 給我一個支點，我可以撐起整個地球

constructor TNavToolBar.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  parent:=TWinControl(AOwner); //可暫時解決你無parent之問題   
  FVisibleButtons := [nbFirst, nbPrior, nbNext, nbLast, nbInsert,   
                      nbDelete, nbEdit, nbPost, nbCancel, nbRefresh];
  InitButtons;
end;    procedure TNavToolBar.InitButtons;
var
  i: TNavBtn;
  Btn: TToolButton;
begin
  ShowMessage(Self.Name);  //你未給name當然是空白
元件不會自動有Name, DesignTime所以有name是Delphi的FormDesigner經由Designer.UniqueName來取得的,一般來說你可以不管
  for i := Low(Buttons) to High(Buttons) do
  begin
    Btn := TToolButton.Create(Owner);
    Btn.Parent := Self;  //=>ERROR: Control '' has no parent window.
//此時你的TNavToolBar本身尚無parent, 故無法做為parent
    Buttons[i] := Btn;
  end;
end;

unit UNAV_TOOLBAR;    interface    uses
  ComCtrls, Classes, SysUtils, Dialogs, StdCtrls, Controls;    type
  TNavBtn = (nbFirst, nbPrior, nbNext, nbLast, nbInsert, nbDelete, nbEdit, nbPost, nbCancel, nbRefresh);
  TNavBtnSet = set of TNavBtn;      TNavToolBar = class(TToolBar)
  private
    FVisibleButtons: TNavBtnSet;
    procedure SetVisible(Value: TNavBtnSet);
    procedure InitButtons;
  public
    Buttons: array[TNavBtn] of TToolButton;
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
  published
    property VisibleButtons: TNavBtnSet read FVisibleButtons write SetVisible default [nbFirst, nbPrior, nbNext, nbLast, nbInsert, nbDelete, nbEdit, nbPost, nbCancel, nbRefresh];
  end;    procedure Register;    implementation    procedure Register;
begin
  RegisterComponents('APPFII', [TNavToolBar]);
end;    { TNavToolBar }    constructor TNavToolBar.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);      FVisibleButtons := [nbFirst, nbPrior, nbNext, nbLast, nbInsert, nbDelete, nbEdit, nbPost, nbCancel, nbRefresh];      Parent := TWinControl(AOwner);      InitButtons;
end;    destructor TNavToolBar.Destroy;
begin
  inherited Destroy;
end;    procedure TNavToolBar.InitButtons;
var
  i: TNavBtn;
  Btn: TToolButton;
begin
  ShowMessage(Self.Name);  //如下圖所示，一片空白      for i := Low(Buttons) to High(Buttons) do
  begin
    Btn := TToolButton.Create(Owner);
    Btn.Parent := Self;  //=>ERROR: Control '' has no parent window.
    Buttons[i] := Btn;
  end;
end;    procedure TNavToolBar.SetVisible(Value: TNavBtnSet);
var
  i: TNavBtn;
begin
  FVisibleButtons := Value;      for i := Low(Buttons) to High(Buttons) do
  begin
    Buttons[i].Visible := i in FVisibleButtons;
    Buttons[i].Enabled := Buttons[i].Visible;
  end;
end;    end.

請加上uses Controls， 及在Create加上Parent := TWinControl(AOwner); 試試看！ Ian

procedure TNavToolBar.InitButtons;
var
  i: TNavBtn;
  Btn: TToolButton;
begin
  for i := Low(NavBtns) to High(NavBtns) do
  begin
    Btn := TToolButton.Create(Self);
    Btn.Parent := Self;
    NavBtns[i] := Btn;
  end;
end;

加上紅色那一行後，程式可以執行了，可是又發現了兩個新的問題ㄟ。 1. 執行時會出現錯誤。錯誤訊息為： Project Project1.exe raised exception class EClassNotFound with message 'Class TToolButton not found'. Process stopped. Use Step or Run to Continue. 2. 在 Design Time 時，我建立一個 Project，將 TNavToolBar 物件拉到 TForm 上，TNavToolBar 會自動建立 10 個 TToolButton 物件；可是當我把 Project 存檔後再開啟時，他就變成 20 個 TToolButton 物件？我再猜應該是第一次建立時，建立了 10 個 TToolButton，第二次開啟 Project 時，又自動建立 10 個，變成一個 20 個 TToolButton 物件。為什麼會這樣？ -------------------------------- 給我一個支點，我可以撐起整個地球