private void frmLapHoaDon_Load(object sender, EventArgs e)
{
colMa.DataSource = myHang.HienBangHang();
colMa.DisplayMember = "TenSP";
colMa.ValueMember = "MaSP";
cmbMaKH.DataSource = myKH.HienBangKH();
cmbMaKH.DisplayMember = "HoTen";
cmbMaKH.ValueMember = "MaKhachHang";
cmbTenNV.DataSource = myNV.HienBangNV();
cmbTenNV.DisplayMember = "HoTen";
cmbTenNV.ValueMember = "MaNhanVien";
}
void HienKH()
{
dgvDanhMuc.DataSource = myKH.HienBangKH();
}