private void dgvChiTietHoaDon_RowEnter(object sender, DataGridViewCellEventArgs e) { int dong = e.RowIndex; txtMaSach.Text = dgvChiTietHoaDon.Rows[dong].Cells[1].Value.ToString(); txtTenSach.Text = Sach_BUS.Laytensach(int.Parse(txtMaSach.Text)); txtDonGia.Text = dgvChiTietHoaDon.Rows[dong].Cells[3].Value.ToString(); txtSoLuong.Text = dgvChiTietHoaDon.Rows[dong].Cells[2].Value.ToString(); txtThanhTien.Text = dgvChiTietHoaDon.Rows[dong].Cells[4].Value.ToString(); }