public void Add()
        {
            GetError("BeginHour", "EndHour", "Limit", "City");

            if (Errors.Count < 1)
            {
                var limit = new MeasurementLimit(BeginHour, EndHour, Limit, City);

                MeasurementLimit.AllMeasurementLimits.Insert(0, limit);

                MeasurementLimits.Clear();
                foreach (var c in MeasurementLimit.AllMeasurementLimits)
                {
                    MeasurementLimits.Add(c);
                }

                SelectedItem = limit;
            }
            else
            {
                StringBuilder sb = new StringBuilder();
                foreach (var k in Errors.Keys)
                {
                    sb.Append($"Ошибка в поле {k}: {Errors[k]};");
                }

                Errors.Clear();

                MessageBox.Show(sb.ToString());
            }
        }
        public void Find()
        {
            MeasurementLimits.Clear();

            var list =
                MeasurementLimit.AllMeasurementLimits
                .Where(m => CityForFind == null || CityForFind.Id == AllCity.Id ||
                       m.City.Id == CityForFind.Id).ToList();

            foreach (var m in list)
            {
                MeasurementLimits.Add(m);
            }

            SelectedItem = null;
        }