private void ThongTinLop_Load(object sender, EventArgs e)
{
List <string> khs = Lbus.GetDanhSachKhoaHoc();
comboBoxKhoaHoc.DataSource = khs;
comboBoxKhoaHoc.SelectedItem = Lbus.GetKhoaHoc(ID);
hocSinhs = HSbus.XemTatCaHSLop(this.ID);
dataGridViewDS_HS.DataSource = hocSinhs;
ReName();
List <string> gvs = GVbus.XemDanhSachTenGV();
comboBoxGVCN.DataSource = gvs;
textBoxLop.Text = Lbus.GetTenLop(ID);
comboBoxGVCN.SelectedItem = gvs.FirstOrDefault(x => x.Contains(tenGV));
}