private void frmThemHoaDon_Load(object sender, EventArgs e)
 {
     //NguoiDungBUS nguoiDung = new NguoiDungBUS();
     cbNhanVien.DataSource     = ndBus.GetDataID_Ten();
     cbNhanVien.DisplayMember  = "tenND";
     cbNhanVien.ValueMember    = "maND";
     cbMaMatHang.DataSource    = kBus.GetDataID_TenSP();
     cbMaMatHang.DisplayMember = "maMH";
     cbMaMatHang.ValueMember   = "maMH";
     // dataThemMH.DataSource = kBus.GetDataThemMH(cbMaMatHang.SelectedValue.ToString());
 }