public void HienThiDS_HH() { DataTable dt_hh = pn.LayDS_HH(); cbb_TenMatHang.DataSource = dt_hh; cbb_TenMatHang.DisplayMember = "TenHang"; cbb_TenMatHang.ValueMember = "MaHang"; if (cbb_TenMatHang.Items.Count > 0) { cbb_TenMatHang.SelectedIndex = 0; } }