Get components of dynamic internal table
With ABAP 7.40 you can use the cast operator to get the components of a dynamic table in one line.
rt_components = CAST cl_abap_structdescr( CAST cl_abap_tabledescr( cl_abap_typedescr=>describe_by_data( lt_table ) )->get_table_line_type( ) )->get_components( ).