public NetworkDiagramAggregationType AggregationType {get;}

public void GetDiagramAggregation(NetworkDiagram networkDiagram)
{
  IReadOnlyList<DiagramAggregation> aggregations = networkDiagram.GetAggregations();
  foreach (var aggregation in aggregations)
  {
    var type = aggregation.AggregationType;
  }
}