private void okBtn_Click(object sender, RoutedEventArgs e) { COURSE course = new COURSE(); TAsLogin taLogin = new TAsLogin(); try { if (coursesCombobox.SelectedValue.ToString() == "Structure Programming") { course = COURSE.STRUCTURE_PROGRAMMING; taLogin.setCourse(course.ToString()); } else { course = COURSE.OOP; taLogin.setCourse(course.ToString()); } taLogin.Show(); this.Close(); } catch (Exception ex) { MessageBox.Show("You must choose a course first!"); } }