演示：

unit Unit1;

interface

uses

  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,

  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ComCtrls, Vcl.ExtCtrls;

type

  TForm1 = class(TForm)

    Timer1: TTimer;

    ProgressBar1: TProgressBar;

    Label1: TLabel;

    procedure FormCreate(Sender: TObject);

    procedure Timer1Timer(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;

var

  Form1: TForm1;

  Limit: Integer;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);

begin

  Limit:= 10;

  Label1.Caption:= '离定时期限还有'+IntToStr(Limit)+'秒..';

end;

procedure TForm1.Timer1Timer(Sender: TObject);

begin

  if Limit<=0 then

  begin

    Timer1.Enabled:= False;

    Close;

  end

  else

  begin

    ProgressBar1.Position:= 30-Limit;

    Label1.Caption:= '离定时期限还有'+IntToStr(Limit)+'秒..';

    Dec(Limit);

  end;

end;

end.