IGeometry geo = feature.ShapeCopy;
IGeometryCollection
pPolyline = geo as IGeometryCollection;
ISegmentCollection pRing;
IGeometryCollection pPolygon =
new PolygonClass();
object ob = Type.Missing;
for (int i = 0; i < pPolyline.GeometryCount; i++)
{
pRing = new RingClass();
pRing.AddSegmentCollection(pPolyline.get_Geometry(i) as
ISegmentCollection);
pPolygon.AddGeometry(pRing as
IGeometry, ref ob, ref ob);
}
Polyline转Polygon,布布扣,bubuko.com
原文：http://www.cnblogs.com/fatherZyl/p/3737326.html