I used follow code to create a polygon:
IPolygonPtr poly;
poly.CreateInstance(CLSID_Polygon);
IGeometryCollectionPtr pGeos;
poly->QueryInterface(&pGeos);
for( int i = 0;.....
{
IRingPtr ring;
ring.CreateInstance(CLSID_Ring);
IPointCollectionPtr ps;
ring->QueryInterface(&ps);
for (long j = 0;..........
{
IPointPtr pnt;
pnt.CreateInstance(CLSID_Point);
pnt->PutCoords(p .x, p .y);
ps->AddPoint(pnt);
}
HRESULT hr = pGeos->AddGeometry(ring, NULL, NULL);
}
After create it , I want to get the Exterior ring to check its direction. I use get_ExteriorRingBag method, And I got nothing? Why the exterior rings is NULL?
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