private void button9_Click(object sender, EventArgs e)
{
DataDAO dataDAO = new DataDAO();
HocPhan hocPhan = new HocPhan();
hocPhan.Ma_HP = textBox8.Text;
hocPhan.Ten_HP = textBox9.Text;
dataDAO.UpdateHP(textBox8.Text, hocPhan);
Deletetextbox();
}