private void SaveFacilityTank(object facilityTankInstance)
        {
            FacilityTankViewModel facilityTankViewModel = facilityTankInstance as FacilityTankViewModel;

            if (facilityTankViewModel.FacilityTank != null)
            {
                if (!facilityTankViewModel.IsValid)
                {
                    Application.Current.MainPage.DisplayAlert("Предупреждение", "Задайте название емкости", "Ok");
                    return;
                }

                using (AppDbContext db = App.GetContext())
                {
                    if (facilityTankViewModel.FacilityTank.FacilityTankId == 0)
                    {
                        db.Entry(facilityTankViewModel.FacilityTank).State = EntityState.Added;
                    }
                    else
                    {
                        db.FacilityTanks.Update(facilityTankViewModel.FacilityTank);
                    }
                    db.SaveChanges();
                }
            }
            Back();
        }
        private void DeleteFacilityTank(object facilityTankInstance)
        {
            FacilityTankViewModel facilityTankViewModel = facilityTankInstance as FacilityTankViewModel;

            if (facilityTankViewModel.FacilityTank.FacilityTankId != 0)
            {
                using (AppDbContext db = App.GetContext())
                {
                    db.FacilityTanks.Remove(facilityTankViewModel.FacilityTank);
                    db.SaveChanges();
                }
            }
            Back();
        }