Arcgis---画线

        public void DrawLine(IPoint p1, IPoint p2)        {            IPolyline line = new PolylineClass();            object _missing = Type.Missing;            line.FromPoint = p1;            line.ToPoint = p2;            ISimpleLineSymbol lineSymbol = new SimpleLineSymbolClass();            lineSymbol.Color = ColorUtilities.GetColor(255, 0, 0);            lineSymbol.Width = 0.25;            ILineElement lineElement = new LineElementClass();            lineElement.Symbol = lineSymbol;            IElement element = lineElement as IElement;            element.Geometry = line as IGeometry;            IGraphicsLayer pLayer = (GISMapApplication.Instance.Scene as IBasicMap).BasicGraphicsLayer;            IGraphicsContainer3D pGC = pLayer as IGraphicsContainer3D;            pGC.AddElement(element);        }