private void FrmUpdateKhachHang_Load(object sender, EventArgs e)
 {
     khbus = new UpdateKhachHangBUS();
     dtQG  = new DataTable();
     disable();
     loadKH();
 }
        private void loadcomboboxQG()
        {
            dtQG  = new DataTable();
            khbus = new UpdateKhachHangBUS();
            dtQG  = khbus.loadQG();

            for (int i = 0; i < dtQG.Rows.Count; i++)
            {
                comboQuocTich.Items.Add(dtQG.Rows[i][1].ToString());
            }
        }