我找到一些資料關於設計可自動顯示時間的 Label 元件 source 但都是動態建立一個 TTimer 做時間的顯示 而我卻想利用 WinAPI - SetTimer() 來做時間的顯示的驅動器 以下為我的元件程式碼 但在傳入參數 Handle 的部分一直出現錯誤 我猜是因為繼承 TLabel 沒有 Handle 的原因 但如此就無法使用SetTimer() 了嗎 ? 另外,繼承 TLabel 的元件,不需要 destructor TMyTimerLabel.Destroy; 這個解構函式嗎 ? 我看別人的元件範例都沒有,但此例我還是把它加入 ...    

 
unit MyTimerLabel;    interface    uses
  SysUtils, Classes, Controls, StdCtrls, Messages, Windows;    type
  TMyTimerLabel = class(TLabel)
  private
    { Private declarations }
  protected
    { Protected declarations }
    procedure WMTimer(var Message:TMessage); message WM_TIMER;
  public
    { Public declarations }
    constructor Create(AOwner : TComponent); override;
    destructor  Destroy; override;      published
    { Published declarations }
  end;    procedure Register;    implementation    constructor TMyTimerLabel.Create(AOwner : TComponent);
begin
  inherited Create(AOwner);
  SetTimer(Handle,1,1000,nil);
end;    destructor TMyTimerLabel.Destroy;
begin
  KillTimer(Handle,1);
  inherited Destroy;
end;    procedure TMyTimerLabel.WMTimer(var Message:TMessage);
var S:string;
begin
  s:=DateTimeToStr(Now);
  Caption:=s;
end;    procedure Register;
begin
  RegisterComponents('MyWay', [TMyTimerLabel]);
end;    end.

 
unit MyTimerLabel;    interface    uses
  SysUtils, Classes, Controls, StdCtrls, Messages, Windows;    type
  TMyTimerLabel = class(TLabel)
  private
    { Private declarations }
    Handle: THandle;
  protected
    { Protected declarations }
    procedure WMTimer(var Message:TMessage); message WM_TIMER;
  public
    { Public declarations }
    constructor Create(AOwner : TComponent); override;
    destructor  Destroy; override;      published
    { Published declarations }
  end;    procedure Register;    implementation    constructor TMyTimerLabel.Create(AOwner : TComponent);
begin
  inherited Create(AOwner);
  Handle := AllocateHWnd(WMTimer);
  SetTimer(Handle,1,1000,nil);
end;    destructor TMyTimerLabel.Destroy;
begin
  KillTimer(Handle,1);
  DeallocateHWnd(Handle);
  inherited Destroy;
end;    procedure TMyTimerLabel.WMTimer(var Message:TMessage);
var S:string;
begin
  if Message.Msg=WM_TIMER then begin
    s:=DateTimeToStr(Now);
    Caption:=s;
  end;
  Message.Result := 0;
end;    procedure Register;
begin
  RegisterComponents('MyWay', [TMyTimerLabel]);
end;    end.

william 兄果然是高手 測試 OK 程式中有些地方我還看不太懂 不過這篇我會好好研究