Memindahkan Item pada list Box

unit Unit1;

interface

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

type
TForm1 = class(TForm)
ListBox1: TListBox;
BitBtn1: TBitBtn;
BitBtn2: TBitBtn;
procedure BitBtn1Click(Sender: TObject);
procedure BitBtn2Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.BitBtn1Click(Sender: TObject);
var
CurrIndex: Integer;
begin
if ListBox1.ItemIndex > 0 then
begin
CurrIndex := ListBox1.ItemIndex;
ListBox1.Items.Move(ListBox1.ItemIndex, (CurrIndex - 1));
ListBox1.ItemIndex := CurrIndex - 1;
end;
end;

procedure TForm1.BitBtn2Click(Sender: TObject);
var
CurrIndex, LastIndex: Integer;
begin
CurrIndex := ListBox1.ItemIndex;
lastindex := ListBox1.Items.Count;

if ListBox1.ItemIndex <> -1 then
begin
if CurrIndex + 1 < lastindex then
begin
ListBox1.Items.Move(ListBox1.ItemIndex, (CurrIndex + 1));
ListBox1.ItemIndex := CurrIndex + 1;
end;
end;
end;

end.