Revit二次开发—ISelectionFilter接口过滤用户选择

public static IList<Element> GetManyRefByRectangle(UIDocument doc)
{
        ReferenceArray ra = new ReferenceArray();
        ISelectionFilter selFilter = new MassSelectionFilter();
        IList<Element> eList = doc.Selection.PickElementsByRectangle(selFilter, 
                "Select multiple faces") as IList<Element>;
        return eList;
}
public class MassSelectionFilter : ISelectionFilter
{
        public bool AllowElement(Element element)
        {
        if (element.Category.Name == "Mass")
        {
                return true;
        }
        return false;
        }
        public bool AllowReference(Reference refer, XYZ point)
        {
                return false;
        }
}

public void SelectPlanarFaces(Autodesk.Revit.DB.Document document)
{
        UIDocument uidoc = new UIDocument(document);
        ISelectionFilter selFilter = new PlanarFacesSelectionFilter(document);
        IList<Reference> faces = uidoc.Selection.PickObjects(ObjectType.Face, 
                selFilter, "Select multiple planar faces");
}
public class PlanarFacesSelectionFilter : ISelectionFilter
{
        Document doc = null;
        public PlanarFacesSelectionFilter(Document document)
        {
                doc = document;
        }
        public bool AllowElement(Element element)
        {
                return true;
        }
        public bool AllowReference(Reference refer, XYZ point)
        {   
                if (doc.GetElement(refer).GetGeometryObjectFromReference(refer) is PlanarFace)
                {
                        // Only return true for planar faces. Non-planar faces will not be selectable 
                        return true; 
                }
                return false;
        }
}