private void MonHoc_Load(object sender, EventArgs e) { dataGridViewDS_MH.DataSource = monhocbus.XemTatCaMonHoc(); textBoxTongSo.Text = (dataGridViewDS_MH.RowCount).ToString(); dataGridViewDS_MH.Columns[0].HeaderText = "Mã MH"; dataGridViewDS_MH.Columns[1].HeaderText = "Tên MH"; dataGridViewDS_MH.Columns[2].HeaderText = "Mã Khoa"; }