[NumLock]

Код:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TMyThread = class(TThread)
  private
    dummy: Integer;
    procedure Updt;
  protected
    procedure Execute; override;
  end;

  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Label1: TLabel;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  MyThread: TMyThread;

implementation

{$R *.dfm}

{ TMyThread }

procedure TMyThread.Execute;
begin
  dummy:=0;
  while not Terminated do
  begin
    Synchronize(Updt);
    Sleep(100);
    Inc(dummy);
  end;
  dummy:=MaxInt;
  Synchronize(Updt);
end;

{ TForm1 }

procedure TMyThread.Updt;
begin
  Form1.Label1.Caption:=IntToStr(dummy);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  if MyThread=nil then
  begin
    MyThread:=TMyThread.Create(True);
    MyThread.FreeOnTerminate:=False;
    MyThread.Resume;
  end;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  if MyThread<>nil then
  begin
    MyThread.Terminate;
    MyThread.WaitFor;
    FreeAndNil(MyThread);
  end;
end;

end.

http://data.cod.ru/73913