I have this code... in Class
METHOD refresh_tree.
DATA ls_tree_nodes LIKE LINE OF tree_nodes.
me->delete_all_nodes( ).
LOOP AT me->tree_nodes INTO ls_tree_nodes.
* Knoten anfügen
me->add_line(
EXPORTING
i_id = ls_tree_nodes-id
i_dirname = ls_tree_nodes-dirname
i_sap_dir = ls_tree_nodes-sap_dir
i_folder = ls_tree_nodes-is_complex
i_changedate = ls_tree_nodes-changedate
i_size = ls_tree_nodes-size
).
ENDLOOP.