private void btnIspitniRok_Click(object sender, RoutedEventArgs e)
        {
            GlavniPanel.Children.Clear();
            StudentPrikazIspitnihRokova p = new StudentPrikazIspitnihRokova();

            GlavniPanel.Children.Add(p);
        }
        private void btnIspitniRokovi_Click(object sender, RoutedEventArgs e)
        {
            DataTable ispitniRok = new DataTable();

            ispitniRok = DBController.PrikaziIspitniRok();
            if (ispitniRok.Rows.Count == 0)
            {
                MessageBox.Show("Jos nije poceo ispitni rok");
            }
            else
            {
                GlavniPanel.Children.Clear();

                StudentPrikazIspitnihRokova spir = new StudentPrikazIspitnihRokova();
                GlavniPanel.Children.Add(spir);
            }
        }