private void load_data_2_tree()
{
US_DM_DON_VI v_us_dv = new US_DM_DON_VI();
DS_DM_DON_VI v_ds_dv = new DS_DM_DON_VI();
v_us_dv.FillDataset(v_ds_dv);
m_tree_don_vi.ParentFieldName = DM_DON_VI.ID_DON_VI_CAP_TREN;
m_tree_don_vi.DataSource = v_ds_dv.Tables[0];
m_tree_don_vi.RefreshDataSource();
m_tree_don_vi.ExpandAll();
}