private void SaveAs(object param)
        {
            try
            {
                if (_model == null)
                {
                    return;
                }

                var filepath = _dialogService.ChooseSaveFile(_fileExtension, _fileFilter);
                if (filepath == null)
                {
                    return;
                }

                _openFile = filepath;
                Save(param);
            }
            catch (Exception ex)
            {
                _dialogService.ShowMessage(ex.ToString());
            }
        }