Arcengine将圆形、矩形转换为多边形；ICircularArc、IEnvelope转化为IPolygon

1、将ICircularArc转化为IPolygon

 1    1: ICircularArc pCircularArc = null;
 2    2: IRubberBand pRubberBand = new RubberCircleClass();
 3    3: pCircularArc = pRubberBand.TrackNew(axMapControl_Main.ActiveView.ScreenDisplay, null) as ICircularArc;
 4    4: if (pCircularArc == null)
 5    5:     return;
 6    6: object missing = Type.Missing;
 7    7: ISegmentCollection pSegmentColl = new RingClass();
 8    8: pSegmentColl.AddSegment((ISegment)pCircularArc, ref missing, ref missing);
 9    9: IRing pRing = (IRing)pSegmentColl;
10   10: pRing.Close(); //得到闭合的环
11   11: IGeometryCollection pGeometryCollection = new PolygonClass();
12   12: pGeometryCollection.AddGeometry(pRing, ref missing, ref missing); //环转面
13   13: IPolygon pPolygon = (IPolygon)pGeometryCollection;

2、将IEnvelope转化为IPolygon

 1: IEnvelope pEnvelope = null;
   2: IRubberBand pRubberBand = new RubberEnvelopeClass();
   3: pEnvelope = pRubberBand.TrackNew(axMapControl_Main.ActiveView.ScreenDisplay, null) as IEnvelope;
   4: if (pEnvelope == null)
   5:     return;           
   6: IPoint p1 = new PointClass();
   7: IPoint p2 = new PointClass();
   8: IPoint p3 = new PointClass();
   9: IPoint p4 = new PointClass();
  10: p1 = pEnvelope.UpperLeft;
  11: p2 = pEnvelope.LowerLeft;
  12: p3 = pEnvelope.LowerRight;
  13: p4 = pEnvelope.UpperRight;
  14: IPointCollection pPointCollection = new PolygonClass();
  15: object missing = Type.Missing;
  16: pPointCollection.AddPoint(p1, ref missing, ref missing);
  17: pPointCollection.AddPoint(p2, ref missing, ref missing);
  18: pPointCollection.AddPoint(p3, ref missing, ref missing);
  19: pPointCollection.AddPoint(p4, ref missing, ref missing);
  20: IPolygon pPolygon = (IPolygon)pPointCollection;