public enum GeometryType : System.Enum, System.IComparable, System.IConvertible, System.IFormattable, System.ISpanFormattable  

IEnumerable<Geometry> MultipartToSinglePart(Geometry inputGeometry)
{
  // list holding the part(s) of the input geometry
  List<Geometry> singleParts = new List<Geometry>();

  // check if the input is a null pointer or if the geometry is empty
  if (inputGeometry == null || inputGeometry.IsEmpty)
    return singleParts;

  // based on the type of geometry, take the parts/points and add them individually into a list
  switch (inputGeometry.GeometryType)
  {
    case GeometryType.Envelope:
      singleParts.Add(inputGeometry.Clone() as Envelope);
      break;
    case GeometryType.Multipatch:
      singleParts.Add(inputGeometry.Clone() as Multipatch);
      break;
    case GeometryType.Multipoint:
      var multiPoint = inputGeometry as Multipoint;

      foreach (var point in multiPoint.Points)
      {
        // add each point of collection as a standalone point into the list
        singleParts.Add(point);
      }
      break;
    case GeometryType.Point:
      singleParts.Add(inputGeometry.Clone() as MapPoint);
      break;
    case GeometryType.Polygon:
      var polygonNew = inputGeometry as Polygon;

      foreach (var polygonPart in polygonNew.Parts)
      {
        // use the PolygonBuilderEx turning the segments into a standalone 
        // polygon instance
        singleParts.Add(PolygonBuilderEx.CreatePolygon(polygonPart));
      }
      break;
    case GeometryType.Polyline:
      var polylineNew = inputGeometry as Polyline;

      foreach (var polylinePart in polyline.Parts)
      {
        // use the PolylineBuilderEx turning the segments into a standalone
        // polyline instance
        singleParts.Add(PolylineBuilderEx.CreatePolyline(polylinePart));
      }
      break;
    case GeometryType.Unknown:
      break;
    default:
      break;
  }
  return singleParts;
}