// 1 class nữa

        #endregion

        #endregion

        #region MH
        private void btnLuu_MH_Click(object sender, EventArgs e)
        {
            if (flag == "thêm")
            {
                DTO_mh.MonHoc_MaMonHoc       = txtMaMH.Text;
                DTO_mh.MonHoc_TenMonHoc      = txtTenMh.Text;
                DTO_mh.MonHoc_MaKhoa         = cmbMaKhoa_MH.SelectedValue.ToString();
                DTO_mh.MonHoc_TinChiLyThuyet = (int)numSoTietLT.Value;
                DTO_mh.MonHoc_TinChiThucHanh = (int)numSoTietTH.Value;

                bool hinhthuc = false;
                if (rdMonbatbuoc.Checked == true)
                {
                    hinhthuc = true;
                }
                else if (rdMontuchon.Checked == true)
                {
                    hinhthuc = false;
                }
                DTO_mh.MonHoc_LoaiMonHoc = hinhthuc;
                BUS_mh.ThemMonHoc(DTO_mh.MonHoc_MaMonHoc, DTO_mh.MonHoc_TenMonHoc, DTO_mh.MonHoc_LoaiMonHoc, DTO_mh.MonHoc_TinChiLyThuyet, DTO_mh.MonHoc_TinChiThucHanh, DTO_mh.MonHoc_MaKhoa);
                dgvMonhoc.DataSource = BUS_mh.LoadDLMonHoc();
                BUS_xuly.ClearAllTextBox(groupBox3);

                int i;
                for (i = 0; i < dgvMonhoc.RowCount - 1; i++)
                {
                    if (dgvMonhoc.Rows[i].Cells[1].Value.ToString() == dgvMonhoc.Text)
                    {
                        break;
                    }
                }
                dgvMonhoc.CurrentCell = dgvMonhoc[0, i];



                DisEnable_MH();
                dgvMonhoc.Enabled    = true;
                btnSua_MH.Enabled    = true;
                btnCancel_MH.Enabled = true;
                btnThem_MH.Visible   = true;
            }
            else if (flag == "sửa")
            {
                DTO_mh.MonHoc_MaMonHoc       = txtMaMH.Text;
                DTO_mh.MonHoc_TenMonHoc      = txtTenMh.Text;
                DTO_mh.MonHoc_MaKhoa         = cmbMaKhoa_MH.SelectedValue.ToString();
                DTO_mh.MonHoc_TinChiLyThuyet = (int)numSoTietLT.Value;
                DTO_mh.MonHoc_TinChiThucHanh = (int)numSoTietTH.Value;

                bool hinhthuc = false;
                if (rdMonbatbuoc.Checked == true)
                {
                    hinhthuc = true;
                }
                else if (rdMontuchon.Checked == true)
                {
                    hinhthuc = false;
                }
                DTO_mh.MonHoc_LoaiMonHoc = hinhthuc;
                BUS_mh.CapNhatMonHoc(DTO_mh.MonHoc_MaMonHoc, DTO_mh.MonHoc_TenMonHoc, DTO_mh.MonHoc_LoaiMonHoc, DTO_mh.MonHoc_TinChiLyThuyet, DTO_mh.MonHoc_TinChiThucHanh, DTO_mh.MonHoc_MaKhoa);
                dgvMonhoc.DataSource = BUS_mh.LoadDLMonHoc();
                BUS_xuly.ClearAllTextBox(groupBox3);

                int i;
                for (i = 0; i < dgvMonhoc.RowCount - 1; i++)
                {
                    if (dgvMonhoc.Rows[i].Cells[1].Value.ToString() == dgvMonhoc.Text)
                    {
                        break;
                    }
                }
                dgvMonhoc.CurrentCell = dgvMonhoc[0, i];

                DisEnable_MH();
                dgvMonhoc.Enabled    = true;
                btnSua_MH.Enabled    = true;
                btnCancel_MH.Enabled = true;
                btnThem_MH.Visible   = true;
            }
        }