public void loadKhachHang()
        {
            DataTable data = cusBUS.getCusDatatable();

            cbKhachHang.Properties.DataSource    = data;
            cbKhachHang.Properties.DisplayMember = "TenKH";
            cbKhachHang.Properties.ValueMember   = "MaKH";
            cbKhachHang.ItemIndex = 0;
        }