private void k_Click(object sender, RoutedEventArgs e)
        {
            MainBox.Clear();

            foreach (var I in Database.StudentsReturn("SELECT * FROM Names ORDER BY AverageScore"))
            {
                MainBox.AppendText($"{I}\n");
            }
        }
        private void ShowAll(object sender, RoutedEventArgs e)
        {
            MainBox.Clear();


            foreach (var I in Database.StudentsReturn("SELECT * FROM Names"))
            {
                MainBox.AppendText($"{I}\n");
            }
        }