public PolygonBuilderEx( 
   IEnumerable<MapPoint> points,
   AttributeFlags attributes,
   SpatialReference spatialReference
)

{
  // list of points
  List<MapPoint> pointsForBuilder = new List<MapPoint>
{
  MapPointBuilderEx.CreateMapPoint(0, 0, 2, 3, 1),
  MapPointBuilderEx.CreateMapPoint(1, 1, 5, 6),
  MapPointBuilderEx.CreateMapPoint(2, 1, 6),
  MapPointBuilderEx.CreateMapPoint(0, 0)
};

  // will have attributes because it is created with convenience method
  Polyline polylineWithAttrs = PolylineBuilderEx.CreatePolyline(pointsForBuilder);
  bool hasZ = polylineWithAttrs.HasZ;          // hasZ = true
  bool hasM = polylineWithAttrs.HasM;          // hasM = true
  bool hasID = polylineWithAttrs.HasID;        // hasID = true

  // will not have attributes because it is specified as a parameter
  Polyline polylineWithoutAttrs =
    PolylineBuilderEx.CreatePolyline(pointsForBuilder, AttributeFlags.None);
  hasZ = polylineWithoutAttrs.HasZ;          // hasZ = false
  hasM = polylineWithoutAttrs.HasM;          // hasM = false
  hasID = polylineWithoutAttrs.HasID;        // hasID = false

  // will have attributes because it is created with convenience method
  Polygon polygonWithAttrs = PolygonBuilderEx.CreatePolygon(pointsForBuilder);
  hasZ = polygonWithAttrs.HasZ;               // hasZ = true
  hasM = polygonWithAttrs.HasM;               // hasM = true
  hasID = polygonWithAttrs.HasID;             // hasID = true

  // will not have attributes because it is specified as a parameter
  Polygon polygonWithoutAttrs =
        PolygonBuilderEx.CreatePolygon(pointsForBuilder, AttributeFlags.None);
  hasZ = polygonWithoutAttrs.HasZ;               // hasZ = false
  hasM = polygonWithoutAttrs.HasM;               // hasM = false
  hasID = polygonWithoutAttrs.HasID;             // hasID = false

  // will not have attributes because it is specified as a parameter
  PolylineBuilderEx polylineB =
             new PolylineBuilderEx(pointsForBuilder, AttributeFlags.None);
  hasZ = polylineB.HasZ;                      // hasZ = false
  hasM = polylineB.HasM;                      // hasM = false
  hasID = polylineB.HasID;                    // hasID = false

  // will have attributes because it is passed an attributed polyline
  polylineB = new PolylineBuilderEx(polylineWithAttrs);
  hasZ = polylineB.HasZ;                      // hasZ = true
  hasM = polylineB.HasM;                      // hasM = true
  hasID = polylineB.HasID;                    // hasID = true

  // will not have attributes because it is passed a non-attributed polyline
  polylineB = new PolylineBuilderEx(polylineWithoutAttrs);
  hasZ = polylineB.HasZ;                      // hasZ = false
  hasM = polylineB.HasM;                      // hasM = false
  hasID = polylineB.HasID;                    // hasID = false

  // will not have attributes because it is specified as a parameter
  PolygonBuilderEx polygonB = new PolygonBuilderEx(pointsForBuilder, AttributeFlags.None);
  hasZ = polygonB.HasZ;                       // hasZ = false
  hasM = polygonB.HasM;                       // hasM = false
  hasID = polygonB.HasID;                     // hasID = false

  // will have attributes because it is passed an attributed polygon
  polygonB = new PolygonBuilderEx(polygonWithAttrs);
  hasZ = polygonB.HasZ;                       // hasZ = true
  hasM = polygonB.HasM;                       // hasM = true
  hasID = polygonB.HasID;                     // hasID = true

  // will not have attributes because it is passed a non-attributed polygon
  polygonB = new PolygonBuilderEx(polygonWithoutAttrs);
  hasZ = polygonB.HasZ;                       // hasZ = true
  hasM = polygonB.HasM;                       // hasM = true
  hasID = polygonB.HasID;                     // hasID = true
}

{
  // Use a builderEx convenience method or use a builderEx constructor.

  MapPoint pt1 = MapPointBuilderEx.CreateMapPoint(1.0, 1.0);
  MapPoint pt2 = MapPointBuilderEx.CreateMapPoint(1.0, 2.0);
  MapPoint pt3 = MapPointBuilderEx.CreateMapPoint(2.0, 2.0);
  MapPoint pt4 = MapPointBuilderEx.CreateMapPoint(2.0, 1.0);

  List<MapPoint> list = new List<MapPoint>() { pt1, pt2, pt3, pt4 };

  Polygon polygonFromPoints = PolygonBuilderEx.CreatePolygon(list, SpatialReferences.WGS84);
  // polygon.HasZ will be false - it is determined by the HasZ flag of the points in the list

  // or specifically use AttributeFlags.NoAttributes
  polygonFromPoints = PolygonBuilderEx.CreatePolygon(list, AttributeFlags.None);

  // use AttributeFlags.None as we have 2D points
  PolygonBuilderEx polygonBuilder = new PolygonBuilderEx(list, AttributeFlags.None);
  polygonBuilder.SpatialReference = SpatialReferences.WGS84;
  polygonFromPoints = polygonBuilder.ToGeometry();
}