public ActionResult SaveCurrency(BL.Model.Currency currency)
        {
            string errorString;
            var    status = ModelState.IsValid;

            if (!ModelState.IsValid)
            {
                errorString = "Ошибки заполнения данных: " + string.Join(", ",
                                                                         ViewData.ModelState.Values.Where(x => x.Errors.Count > 0).Select(v => string.Join(", ",
                                                                                                                                                           v.Errors.Select(e => e.ErrorMessage))));
            }
            else
            {
                status = currencyRepository.AddOrUpdateCurrency(currency, out errorString);
            }

            return(Json(new { status, errorString }));
        }