unit Unit1;

interface
uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants,
  System.Classes, Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls,
  Vcl.WinXCtrls, System.UITypes, Vcl.ExtCtrls;

type
  TTheThread = class(TThread)
  private
    fLabel : TLabel;
  public
    constructor Create(aLabel: TLabel); overload;
    procedure Execute; override;
  end;


type
  TForm1 = class(TForm)
  CounterLabel: TLabel;
    procedure FormCreate(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private-Deklarationen }
    fTheThread: TTheThread;
  public
    { Public-Deklarationen }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}


constructor TTheThread.Create(aLabel: TLabel);
  begin
    fLabel := aLabel;
    inherited Create(False);
  end;

procedure TTheThread.Execute;
 var
    I1, I2: Cardinal;
  begin
    I1 := 0;
    I2 := 0;
    try
      while (not Terminated) do
        begin
          Inc(I1);
          if (I1 >= 1000) then
            begin
              Inc(I2);
              Synchronize(
                procedure
                  begin
                    FLabel.caption := I2.ToString;
                  end);
              I1 := 0;
            end;
        end;
    except
      raise;
// on e: exception do begin
// mache hier irgendetwas mit dem Fehler.
    end;
  end;

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
   fTheThread.Terminate;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  fTheThread := TTheThread.Create(CounterLabel);
end;
end.