OpenDialog文件多选

procedure TForm1.OpenFileListClick(Sender: TObject);
var
  openDialog: TOpenDialog;
  I: Integer;
begin
  openDialog := TOpenDialog.Create(Self);
  openDialog.Filter := 'Excel文件|*.xlsx;*.xls';
  openDialog.DefaultExt := 'xlsx';
  openDialog.Options := [ofAllowMultiSelect];
  try
    if openDialog.Execute then
    begin
      ListBox1.Clear;
      ListBox1.Items.Add('一共打开：' + VarToStr(openDialog.Files.Count) + '个文件;');
      ListBox1.Items.BeginUpdate;
      for I :=  to openDialog.Files.Count -  do
        ListBox1.Items.Add(openDialog.Files[I]);
      ListBox1.Items.EndUpdate;
    end;
  finally
    openDialog.Free;
  end;
end;