private void Dodaj(object sender, RoutedEventArgs e)
        {
            userDlg = new UserDlg();
            Hide();
            userDlg.ShowDialog();
            Show();

            if (userDlg.userAdded)
            {
                usersList.Items.Add(userDlg.user.getUser());
                usersList.Items.Refresh();
                users.Add(userDlg.user);
            }
        }
        private void Edytuj(object sender, RoutedEventArgs e)
        {
            userDlg = new UserDlg();
            Hide();
            userDlg.userEdited = true;
            userDlg.openEdition(users[sel].fName, users[sel].lName, users[sel].eMail);
            userDlg.ShowDialog();
            Show();
            usersList.SelectedIndex = sel;

            if (userDlg.userEditDone)
            {
                users[sel].fName = userDlg.user.fName;
                users[sel].lName = userDlg.user.lName;
                users[sel].eMail = userDlg.user.eMail;
                usersList.Items.Insert(usersList.SelectedIndex, userDlg.user.getUser());
                usersList.Items.Remove(usersList.SelectedItem);
            }
            usersList.Items.Refresh();
        }