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

// list of points
List<MapPoint> points = 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(points);
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(points, 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(points);
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(points, 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(points, 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(points, 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 polygon = 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
polygon = PolygonBuilderEx.CreatePolygon(list, AttributeFlags.None);

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