public MainWindow()
        {
            InitializeComponent();

            DbAction.CreateDatabase();

            if (selection.SelectedIndex == 1)
            {
                selection2.Visibility = Visibility.Hidden;
                itemName.Visibility   = Visibility.Visible;
                selection4.Visibility = Visibility.Visible;

                classList            = new ObservableCollection <Classes>(DbAction.QueryClasses());
                itemsList            = new ObservableCollection <Equipment>(DbAction.QueryItems());
                itemPrice.Visibility = Visibility.Visible;
                if (classList.Count() != 0)
                {
                    selection4.ItemsSource  = classList;
                    actionbutton.Visibility = Visibility.Visible;
                }
                else
                {
                    selection4.IsEnabled = false;
                }
            }
            Classrooms.ItemsSource = classList;
            Items.ItemsSource      = itemsList;
        }
        private void Actionbutton_Click(object sender, RoutedEventArgs e)
        {
            if (selection.SelectedIndex == 0)
            {
                Classes claz = new Classes();
                claz.ClassName = 11;//int.Parse(nameclass.Text);

                DbAction.InsertToDB(claz);
                classList.Add(claz);
            }
        }