private void dataGridViewHDBanHang_CellClick(object sender, DataGridViewCellEventArgs e)
{
try
{
string mahd = dataGridViewHDBanHang.CurrentRow.Cells[0].Value.ToString();
dataGridViewChiTietBanHang.DataSource = bllBanHang.loadCTHoaDon(mahd);
}
catch (Exception)
{
}
}