public static void SetRootNodes( 
   MapView mapView,
   MapMemberIDSet rootNodes
)

await QueuedTask.Run(() =>
{
  var dict = new Dictionary<MapMember, List<long>>();
  dict.Add(entityLayer, oids);
  MapMemberIDSet mmIDSet = MapMemberIDSet.FromDictionary(dict);

  MapView.Active.SetRootNodes(mmIDSet);
});

await QueuedTask.Run(() =>
{
  var mapSel = MapView.Active.Map.GetSelection();

  MapView.Active.SetRootNodes(mapSel);
});

    //using ArcGIS.Core.Data.Knowledge.Extensions;

    await QueuedTask.Run(async() =>
    {
        var ffp_config = new CIMFilteredFindPathsConfiguration();
        ffp_config.Name = "Create Link Chart from FFP Results";
//set up config
//...
        
        var results = kg.RunFilteredFindPaths(ffp_config);

        var pathsEntitiesAndRelationships = results.ExtractPathsEntitiesAndRelationships(null);

        //Create a KG layer id set
        var kgLayerIdSet = KnowledgeGraphLayerIDSet.FromKnowledgeGraphIDSet(
            pathsEntitiesAndRelationships.ToKnowledgeGraphIDSet(
                KGResultContentFromFFP.EntitiesAndRelationships));

        //Create a brand new link chart with the results and show it
        var linkChart = MapFactory.Instance.CreateLinkChart(
                                            "KG Intro", kg, kgLayerIdSet);

        var mapPane = await FrameworkApplication.Panes.CreateMapPaneAsync(linkChart);
        var linkChartView = mapPane.MapView;

        //Change layout algo to match the default used by the UI after FFP
        await linkChartView.SetLinkChartLayoutAsync(
            KnowledgeLinkChartLayoutAlgorithm.Hierarchical_TopToBottom);

        //Set root nodes - they correspond to the origin nodes of the result paths
        var kgLayerIdSetForRootNodes = KnowledgeGraphLayerIDSet.FromKnowledgeGraphIDSet(
            pathsEntitiesAndRelationships.ToKnowledgeGraphIDSet(
                KGResultContentFromFFP.OnlyPathsOriginEntities));

        //To correctly identify the ids in the link chart we must change the ids
        //from Geodatabase oids returned in the KnowledgeGraphLayerIDSet to the
//temporary/synthetic oids used by layers in the link chart...
        var kg_layer = linkChart.GetLayersAsFlattenedList().OfType<KnowledgeGraphLayer>().First();
        var mapMembers = kg_layer.GetMapMembersAsFlattenedList();
        var oidDict = kgLayerIdSetForRootNodes.ToOIDDictionary();
        var mmDict = new Dictionary<MapMember, List<long>>();
        foreach (var kvp in oidDict)
        {
            var named_type = kvp.Key;
            foreach (var mm in mapMembers)
            {
                if (mm is LinkChartFeatureLayer fl_lc && fl_lc.IsEntity)
                {
                    if (fl_lc.GetTypeName().ToLower() == named_type.ToLower())
                    {
                        var lc_oids = new List<long>();
                        //these oids are from the geodatabase
                        var oid_field = $"{fl_lc.GetTypeName()}.objectid";
                        var id_list = string.Join(',', kvp.Value.ToArray());
                        var where = $"{fl_lc.GetTypeName()}.objectid IN ({id_list})";

                        var qf = new ArcGIS.Core.Data.QueryFilter()
                        {
                            WhereClause = where,
                            SubFields = $"LC.OID,{oid_field}"//the 'LC.OID' oids are the ones
                                           //we need for the mapmember id set
                                           //in the link chart
                        };
                        var rc = fl_lc.Search(qf);
                        var oid_idx = rc.FindField(oid_field);
                        while (rc.MoveNext())
                        {
                            var oid = (long)rc.Current[oid_idx];
                            var lc_oid = rc.Current.GetObjectID();
                            lc_oids.Add(lc_oid);
                        }
                        rc.Dispose();
                        mmDict[fl_lc] = lc_oids;
                        break;
                    }
                }
            }
        }

        var mmIdSet = MapMemberIDSet.FromDictionary(mmDict);
        linkChartView.SetRootNodes(mmIdSet);
    });