private void btnPocetna_Click(object sender, RoutedEventArgs e)
        {
            GlavniPanel.Children.Clear();
            StudentPocetnaStrana sp = new StudentPocetnaStrana(student);

            GlavniPanel.Children.Add(sp);
        }
        public StudentWindow(Korisnik k)
        {
            this.student = new Student(k);
            InitializeComponent();

            this.ime.Content = this.student.getIme() + " " + this.student.getPrezime();
            GlavniPanel.Children.Clear();
            StudentPocetnaStrana sp = new StudentPocetnaStrana(student);

            GlavniPanel.Children.Add(sp);
        }