面积测量
在Mapcontrol的mousedown中实现
1 IGeometry pBuffer = m_pMapControl.TrackPolygon(); 2 IPolygon pPoly = pBuffer as IPolygon; 3 if (pBuffer == null || pBuffer.IsEmpty) 4 return; 5 IArea pArea = pBuffer as IArea; 6 double area = pArea.Area; 7 if (pArea.Area < 0) 8 { 9 area = System.Math.Abs(pArea.Area); 10 }