bool    checkMultipart()  //检查是否是多部分要素
{
   IFeaturePtr ipFeature = getFeature();  //选择要素---
   IGeometryPtr ipGeometry;
   ipFeature->get_Shape(&ipGeometry);
    IGeometryCollectionPtr ipGeometryCollection = (IGeometryCollectionPtr)ipGeometry;
   long geometryCount;
   ipGeometryCollection->get_GeometryCount(&geometryCount);  //得到由多少个图形组成；
   if (geometryCount > 1)   //判断大于1时--
   {
      IGeometryPtr ipCheckGeometry, ipNewCheckGeometry;
      for (int i = 0; i < geometryCount-1; i++)
      {
         ipGeometryCollection->get_Geometry(i,&ipCheckGeometry);
         ipGeometryCollection->get_Geometry(i+1, &ipNewCheckGeometry); //该Geometry类型为esriGeometryRing  reason：  because the polygon is included--by  ring;
         IRingPtr ipCheckRing = (IRingPtr)ipCheckGeometry;   //强制转换：
         IRingPtr ipNewCheckRing = (IRingPtr)ipNewCheckGeometry;
         short checkInteriror, checkOuter;
         ipCheckRing->get_IsExterior(&checkInteriror);  // determine whether is 外环
         ipNewCheckRing->get_IsExterior(&checkOuter);
         if (checkInteriror == 0 || checkOuter == 0)
         {
            return false;
         }
         else if(checkInteriror == -1 || checkOuter == -1)
         {
            return true;
         }
      }
   }
   return false;
}