public string ServiceUri {get;}

{
  // get the active investigation view 
  var iv = KnowledgeGraphInvestigationView.Active;
  var serviceUri = iv.Investigation.ServiceUri;

  // build a dictionary of records
  string some_entity = "Entity_Type_Name";
  var dict = new Dictionary<string, List<long>>();
  //Each entry consists of the type name and corresponding lists of ids
  dict.Add(some_entity, new List<long>() { 1, 5, 18, 36, 78 });

  //Create the id set...
  var idSet = KnowledgeGraphLayerIDSet.FromDictionary(new Uri(serviceUri), dict);

  // select the records on the investigation view
  iv.SetSelectedRecords(idSet, SelectionCombinationMethod.New);
}