private void Button1_Click(object sender, EventArgs e)
{
if (listBox1.SelectedItem != null && listBox2.SelectedItem != null)
{
usersRepository.AttachStudent(listBox1.SelectedItem.ToString(), gradesRepository.GetGroupId(listBox2.SelectedItem.ToString()));
listBox1.Items.Clear();
List <Student> students = usersRepository.GetStudents(0);
foreach (Student student in students)
{
listBox1.Items.Add(student.Name + " " + student.Surname);
}
listBox2.Items.Clear();
List <Group> groups = gradesRepository.GetGroups();
foreach (Group group in groups)
{
listBox2.Items.Add(group.Name);
}
}
}