BuildingCoder.CmdRelationshipInverter.Execute C# (CSharp) Method

        public Result Execute(
            ExternalCommandData commandData,
            ref string message,
            ElementSet elements)
        {
            UIApplication app = commandData.Application;
              m_doc = app.ActiveUIDocument.Document;

              // filter for family instance and (door or window):

              ElementClassFilter fFamInstClass = new ElementClassFilter( typeof( FamilyInstance ) );
              ElementCategoryFilter fDoorCat = new ElementCategoryFilter( BuiltInCategory.OST_Doors );
              ElementCategoryFilter fWindowCat = new ElementCategoryFilter( BuiltInCategory.OST_Windows );
              LogicalOrFilter fCat = new LogicalOrFilter( fDoorCat, fWindowCat );
              LogicalAndFilter f = new LogicalAndFilter( fCat, fFamInstClass );
              FilteredElementCollector openings = new FilteredElementCollector( m_doc );
              openings.WherePasses( f );

              // map with key = host element id and
              // value = list of hosted element ids:

              Dictionary<ElementId, List<ElementId>> ids =
            GetElementIds( openings );

              DumpHostedElements( ids );
              m_doc = null;

              return Result.Succeeded;
        }