public class KnowledgeGraphQueryFilter 

//On the QueuedTask...
//and assuming you have established a connection to a knowledge graph
//...
//Construct an openCypher query - return the first 10 entities (whatever
//they are...)
var query = "MATCH (n) RETURN n LIMIT 10";//default limit is 100 if not specified
//other examples...
//query = "MATCH (a:Person) RETURN [a.name, a.age] ORDER BY a.age DESC LIMIT 50";
//query = "MATCH (b:Person) RETURN { Xperson: { Xname: b.name, Xage: b.age } } ORDER BY b.name DESC";
//query = "MATCH p = (c:Person)-[:HasCar]-() RETURN p ORDER BY c.name DESC";

//Create a query filter
//Note: OutputSpatialReference is currently ignored
var kg_qf = new KnowledgeGraphQueryFilter()
{
  QueryText = query
};
//Optionally - u can choose to include provenance in the results
//(_if_ the KG has provenance - otherwise the query will fail)
if (includeProvenanceIfPresent)
{
  //see "Get Whether KG Supports Provenance" snippet
  if (KnowledgeGraphSupportsProvenance(kg))
  {
    //Only include if the KG has provenance
    kg_qf.ProvenanceBehavior = 
      KnowledgeGraphProvenanceBehavior.Include;//default is exclude
  }
}
//submit the query - returns a KnowledgeGraphCursor
using (var kg_rc = kg.SubmitQuery(kg_qf))
{
  //wait for rows to be returned from the server
  //note the "await"...
  while (await kg_rc.WaitForRowsAsync())
  {
    //Rows have been retrieved - process this "batch"...
    while (kg_rc.MoveNext())
    {
      //Get the current KnowledgeGraphRow
      using (var graph_row = kg_rc.Current)
      {
        //Graph row is an array, process all returned values...
        var val_count = (int)graph_row.GetCount();
        for (int i = 0; i < val_count; i++)
        {
          var retval = graph_row[i];
          //Process row value (note: recursive)
          //See "Process a KnowledgeGraphRow Value" snippet
          ProcessKnowledgeGraphRowValue(retval);
        }
      }
    }
  }//WaitForRowsAsync
}//SubmitQuery

QueuedTask.Run(async () =>
{
  //Given an open-cypher qry against an entity or relationship type
  var qry = @"MATCH (p:PhoneNumber) RETURN p LIMIT 10";

  //create a KG query filter
  var kg_qry_filter = new KnowledgeGraphQueryFilter()
  {
    QueryText = qry
  };

  //save a list of the ids
  var oids = new List<long>();
  using (var kgRowCursor = kg.SubmitQuery(kg_qry_filter))
  {
    //wait for rows to be returned asynchronously from the server
    while (await kgRowCursor.WaitForRowsAsync())
    {
      //get the rows using "standard" move next
      while (kgRowCursor.MoveNext())
      {
        //current row is accessible via ".Current" prop of the cursor
        using (var graphRow = kgRowCursor.Current)
        {
          var cell_phone = graphRow[0] as KnowledgeGraphEntityValue;
          //note: some user-managed graphs do not have objectids
          oids.Add(cell_phone.GetObjectID());
        }
      }
    }
  }
  //create a query filter using the oids
  if (oids.Count > 0)
  {
    //select them on the layer
    var qf = new QueryFilter()
    {
      ObjectIDs = oids //apply the oids to the ObjectIds property
    };
    //select the child feature layer or standalone table representing
    //the given entity or relate type whose records are to be selected
    var phone_number_fl = kg_layer.GetLayersAsFlattenedList()
        .OfType<FeatureLayer>().First(l => l.Name == "PhoneNumber");

    //perform the selection
    phone_number_fl.Select(qf);
  }
});