TheAirline.Models.Routes.RouteClassConfiguration.AddFacility C# (CSharp) Method

        public void AddFacility(RouteFacility facility)
        {
            if (Facilities.Exists(f => f.Type == facility.Type))
            {
                Facilities.RemoveAll(f => f.Type == facility.Type);
            }

            Facilities.Add(facility);
        }

        private void btnSaveConfiguration_Click(object sender, RoutedEventArgs e)
        {
            int totalServiceLevel = Classes.Sum(c => c.Facilities.Sum(f => f.SelectedFacility.ServiceLevel));
            var txtName = new TextBox();
            txtName.Width = 200;
            txtName.Background = Brushes.Transparent;
            txtName.Foreground = Brushes.White;
            txtName.Text = string.Format(
                "Configuration {0} (Service level: {1})",
                Configurations.GetConfigurations(Configuration.ConfigurationType.Routeclasses).Count + 1,
                totalServiceLevel);
            txtName.HorizontalAlignment = HorizontalAlignment.Left;

            if (PopUpSingleElement.ShowPopUp(Translator.GetInstance().GetString("PageAirlineWages", "1013"), txtName)
                == PopUpSingleElement.ButtonSelected.OK && txtName.Text.Trim().Length > 2)
            {
                string name = txtName.Text.Trim();
                var configuration = new RouteClassesConfiguration(name, true);

                foreach (AirlineClassMVVM type in Classes)
                {
                    var classConfiguration = new RouteClassConfiguration(type.Type);

                    foreach (AirlineClassFacilityMVVM facility in type.Facilities)
                    {
                        classConfiguration.AddFacility(facility.SelectedFacility);
                    }

                    configuration.AddClass(classConfiguration);
                }

                Configurations.AddConfiguration(configuration);

                btnSave.Visibility = Visibility.Collapsed;
                btnCreate.Visibility = Visibility.Visible;
            }
        }