delphi如何把一个文本列表添加到TListBox并避免重复项

unit Unit1;

interface

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

type
TForm1 = class(TForm)
ListBox1: TListBox;
procedure FormCreate(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
const
FilePath = 'c:\temp\Test.txt';
var
List: TStringList;
begin
List := TStringList.Create;
List.Sorted := True;
List.Duplicates := dupIgnore;
List.LoadFromFile(FilePath);
ListBox1.Items.Assign(List);
List.Free;
end;

end.