private void AddDepartmentAndClassTeacherButton_Click(object sender, EventArgs e)
        {
            if (DepartmentNumberTextBox.Text.Length == 0)
            {
                Warning();
            }
            else
            {
                string[] parts      = GetCurrentClassTeacher().Split('-');
                string   name       = parts[0];
                string   surname    = parts[1];
                int      TeachersId = TeacherRepository.GetIdByName(name, surname);

                int ClassNumber = GetCurrentClassNumber();
                int ClassesId   = ClassesRepository.GetIdByNumber(ClassNumber);

                try
                {
                    int  Title             = int.Parse(DepartmentNumberTextBox.Text);
                    bool isDepartmentAdded = DepartmentsRepository.AddDepartment(Title, TeachersId, ClassesId);
                    if (isDepartmentAdded == true)
                    {
                        PopulateDepartmentsComboBox();
                        DepartmentNumberTextBox.Text = "";
                    }
                }
                catch (Exception)
                {
                    MessageBox.Show("Molimo unesite broj odjeljenja");
                }
            }
        }