Delphi work with TTimer.

Timer.

unit Unit1;

interface

uses

  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants,

  System.Classes, Vcl.Graphics,

  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.ExtCtrls, JvExControls,

  JvNavigationPane, Vcl.StdCtrls, Vcl.ComCtrls;

type

  TForm1 = class(TForm)

    JvNavPanelHeader1: TJvNavPanelHeader;

    Timer1: TTimer;

    procedure Timer1Timer(Sender: TObject);

    procedure FormCreate(Sender: TObject);

    procedure FormResize(Sender: TObject);

  private

    { Private declarations }

    Lap: word;

  public

    { Public declarations }

  end;

var

  Form1: TForm1;

  SYS_CREATE: TDateTime;

  RUN_TIME: TDateTime;

implementation

{$R *.dfm}

uses System.DateUtils;

function SecondToTime(const Seconds: Cardinal): Double;

var

  ms, ss, mm, hh, dd: Cardinal;

begin

  dd := Seconds div SecsPerDay;

  hh := (Seconds mod SecsPerDay) div SecsPerHour;

  mm := ((Seconds mod SecsPerDay) mod SecsPerHour) div SecsPerMin;

  ss := ((Seconds mod SecsPerDay) mod SecsPerHour) mod SecsPerMin;

  ms := 0;

  Result := dd + EncodeTime(hh, mm, ss, ms);

end;

procedure TForm1.FormCreate(Sender: TObject);

begin

  SYS_CREATE := Now;

end;

procedure TForm1.FormResize(Sender: TObject);

begin

  case SElf.WindowState of

    wsMaximized:

      JvNavPanelHeader1.Font.Size := 128;

    wsMinimized, wsNormal:

      JvNavPanelHeader1.Font.Size := 48;

  end;

end;

procedure TForm1.Timer1Timer(Sender: TObject);

begin

  RUN_TIME := SecondToTime(SecondsBetween(SYS_CREATE, Now));

  JvNavPanelHeader1.Caption := formatdatetime('hh:mm:ss', RUN_TIME);

end;

end.