public void loadMaNV()
        {
            MuonTra.ConnectToSQL sql     = new MuonTra.ConnectToSQL();
            SqlDataReader        sqlData = sql.getDataTable("NhanVien");

            while (sqlData.Read())
            {
                cbomanv.Items.Add(sqlData["MaNV"].ToString());
            }
            cbomanv.ValueMember = "MaNV";
        }
        public void showLsvMuonTra()
        {
            clearLstMuonTra();
            MuonTra.ConnectToSQL conn    = new MuonTra.ConnectToSQL();
            SqlDataReader        sqlData = conn.getDataTable("MuonTra");

            while (sqlData.Read())
            {
                addList(sqlData);
            }
        }
        public void loadMaDG()
        {
            MuonTra.ConnectToSQL sql     = new MuonTra.ConnectToSQL();
            SqlDataReader        sqlData = sql.getDataTable("DocGia");

            while (sqlData.Read())
            {
                cbmadg.Items.Add(sqlData["MaDG"].ToString());
            }

            cbmadg.ValueMember = "MaDG";
        }