delphi 請問Timer如果不用拉元件產生的，該如何寫

type
  TDBThread = class(TThread)
  protected
    procedure PrintMsg;
    procedure Execute; override;
  end;
procedure TDBThread.Execute;
begin
  while Not Terminated do
  begin
    Synchronize(PrintMsg);
    Sleep(1500);
  end;
end;
procedure TDBThread.PrintMsg;
begin
  Form1.Memo1.Lines.Add(TimeToStr(Time) + ': Threading');
end;
procedure TForm1.FormShow(Sender: TObject);
begin
  DBThread := TDBThread.Create(False);
end;
procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  DBThread.Terminate;
  DBThread.WaitFor;
  DBThread.Free;
end;
攪個直執行緒Sleep(1500);就是你要它多久做一次(準一點 )