[NumLock]

Код:

unit Unit1;

interface

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

type
  TMyObject = class(TObject)
    i: Integer;
    constructor Create(i: Integer);
  end;

  TForm1 = class(TForm)
    ListBox1: TListBox;
    procedure FormCreate(Sender: TObject);
    procedure ListBox1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{ TMyObject }

constructor TMyObject.Create(i: Integer);
begin
  Self.i:=i;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  ListBox1.Items.AddObject('1', TMyObject.Create(1));
  ListBox1.Items.AddObject('22', TMyObject.Create(22));
end;

procedure TForm1.ListBox1Click(Sender: TObject);
begin
  ShowMessage(IntToStr(TMyObject(ListBox1.Items.Objects[ListBox1.ItemIndex]).i));
end;

end.