Engine中在地图上画线，并将其存入Mxd文档中，可以选中查询其属性值，有没有什么好的办法呢？

ILineElement pLineElement = new LineElementClass();
ISimpleLineSymbol pSimpleFillSymbol = new SimpleLineSymbolClass();
ESRI.ArcGIS.Geometry.IPolyline pPolyline = new ESRI.ArcGIS.Geometry.PolylineClass();
IRubberBand pRubberBand = new RubberLineClass();
pPolyline = (ESRI.ArcGIS.Geometry.IPolyline)pRubberBand.TrackNew(axMapControl1.ActiveView.ScreenDisplay, null);
pSimpleFillSymbol.Color = bf.getRGB(78, 0, 150);
pSimpleFillSymbol.Width = 1;
pSimpleFillSymbol.Style = esriSimpleLineStyle.esriSLSSolid;
IElement pElement = (IElement)pLineElement;
pElement.Geometry = pPolyline;
pLineElement.Symbol = pSimpleFillSymbol;
IGraphicsContainer pGraphicsContainer = (IGraphicsContainer)axMapControl1.Map;
pGraphicsContainer.AddElement((IElement)pLineElement, 0);
axMapControl1.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);我现在这种做法现实了在地图上画线，可是这个线是图片型的，没办法在Mxd文档上查询其属性值