private void ButtonChoose_Click(object sender, EventArgs e) { if ((Type)ComboBoxMain.SelectedItem == typeof(Faculty)) { ActiveForm.Hide(); FormAddFaculty f = new FormAddFaculty(null); f.Show(); } if ((Type)ComboBoxMain.SelectedItem == typeof(Chair)) { ActiveForm.Hide(); FormAddChair f = new FormAddChair(null); f.Show(); } if ((Type)ComboBoxMain.SelectedItem == typeof(Teacher)) { ActiveForm.Hide(); FormAddTeacher f = new FormAddTeacher(null); f.Show(); } if ((Type)ComboBoxMain.SelectedItem == typeof(Discipline)) { ActiveForm.Hide(); FormAddDiscipline f = new FormAddDiscipline(null); f.Show(); } }