[NumLock]

Код:

type
  TForm1 = class(TForm)
    ComboBox1: TComboBox;
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  ComboBox1.Items.LoadFromFile('');
  ComboBox1.Items.Add('xxx');
  ComboBox1.Items.Add('yyy');
end;