public sealed class FindDiagramFeatureQuery 

public void FindDiagramFeatures(NetworkDiagram diagram, List<Guid> globalIDs)
{
  FindDiagramFeatureQuery featureQuery = new FindDiagramFeatureQuery();
  featureQuery.NetworkRowGlobalIDs = globalIDs;
  featureQuery.AddAggregations = true;
  featureQuery.AddConnectivityAssociations = true;
  featureQuery.AddStructuralAttachments = true;

  IReadOnlyList<FindResultItem> features = diagram.FindDiagramFeatures(featureQuery);
  foreach (var findFeature in features)
  {
    long objectID = findFeature.ObjectID;
    Guid guid = findFeature.GlobalID;
    GeometryType geometryType = findFeature.GeometryType;
    int sourceID = findFeature.SourceID;
  }
}