ArcGIS Pro 2.8 API Reference Guide
IsExteriorRing(Int32) Method
Example 

ArcGIS.Core.Geometry Namespace > Polygon Class : IsExteriorRing(Int32) Method
The part index.
Determines if the specified part of this polygon is an exterior ring.
Syntax
public bool IsExteriorRing( 
   int index
)
Public Function IsExteriorRing( _
   ByVal index As Integer _
) As Boolean

Parameters

index
The part index.

Return Value

A boolean indicating if the part is an exterior ring.
Exceptions
ExceptionDescription
The index is negative or is greater than or equal to the number of parts in this polygon.
Remarks
An exterior ring is a part that is oriented clockwise.
Example
public void GetExteriorRings(Polygon inputPolygon)
{
  if (inputPolygon == null || inputPolygon.IsEmpty)
    return;

  // polygon part count
  int partCount = inputPolygon.PartCount;
  // polygon exterior ring count
  int numExtRings = inputPolygon.ExteriorRingCount;
  // get set of exterior rings for the polygon
  IList<Polygon> extRings = inputPolygon.GetExteriorRings();

  // test each part for "exterior ring"
  for (int idx = 0; idx < partCount; idx++)
  {
    bool isExteriorRing = inputPolygon.IsExteriorRing(idx);
  }
}
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

Polygon Class
Polygon Members