public NetworkDiagramAggregationType AggregationType {get;}

{
  // Get the diagram aggregations
  static void GetDiagramAggregation(NetworkDiagram networkDiagram)
  {
    IReadOnlyList<DiagramAggregation> aggregations = networkDiagram.GetAggregations();
    foreach (DiagramAggregation aggregation in aggregations)
    {
      NetworkDiagramAggregationType type = aggregation.AggregationType;
    }
  }
}