public static string GetText(this DataAccess.Enums.PaymentStatus paymentStatus)
        {
            switch (paymentStatus)
            {
            case DataAccess.Enums.PaymentStatus.WaitingForPayment:  return("Waiting for payment");

            case DataAccess.Enums.PaymentStatus.Paid:               return("Paid");

            case DataAccess.Enums.PaymentStatus.Overdue:            return("Overdue");

            case DataAccess.Enums.PaymentStatus.PaidWithDelay:      return("Paid with delay");

            default: throw new System.InvalidOperationException("Wrong enum value");
            }
        }
        public static string ToCssClass(this DataAccess.Enums.PaymentStatus paymentStatus)
        {
            switch (paymentStatus)
            {
            case DataAccess.Enums.PaymentStatus.WaitingForPayment:  return(string.Empty);

            case DataAccess.Enums.PaymentStatus.Paid:               return("paid");

            case DataAccess.Enums.PaymentStatus.Overdue:            return("overdue");

            case DataAccess.Enums.PaymentStatus.PaidWithDelay:      return("paid-with-delay");

            default: throw new System.InvalidOperationException("Wrong enum value");
            }
        }