private void load_data_to_grid()
{
US_GD_HOP_DONG v_us = new US_GD_HOP_DONG();
DataTable v_dt= v_us.FillDatasetBCTangGiamLD( m_dat_tu_ngay.DateTime, m_dat_den_ngay.DateTime).Tables[0];
m_tree_list.ParentFieldName = DM_DON_VI.ID_DON_VI_CAP_TREN;
m_tree_list.DataSource = v_dt;
m_tree_list.ExpandAll();
}