1、將ICircularArc轉化為IPolygon
1: ICircularArc pCircularArc = null;
2: IRubberBand pRubberBand = new RubberCircleClass();
3: pCircularArc = pRubberBand.TrackNew(axMapControl_Main.ActiveView.ScreenDisplay, null) as ICircularArc;
4: if (pCircularArc == null)
5: return;
6: object missing = Type.Missing;
7: ISegmentCollection pSegmentColl = new RingClass();
8: pSegmentColl.AddSegment((ISegment)pCircularArc, ref missing, ref missing);
9: IRing pRing = (IRing)pSegmentColl;
10: pRing.Close(); //得到閉合的環
11: IGeometryCollection pGeometryCollection = new PolygonClass();
12: pGeometryCollection.AddGeometry(pRing, ref missing, ref missing); //環轉面
13: IPolygon pPolygon = (IPolygon)pGeometryCollection;
2、將IEnvelope轉化為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;
注意：在給IPointCollection添加點的時候要按照一定的順序添加（按照順時針或者逆時針的順序選取起點進行添加，否則會使得圖形發生變化）