ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Core.Data.Knowledge Namespace / KnowledgeGraph Class / SubmitQuery Method
The query filter to submit
Example Version

SubmitQuery Method
Performs an openCypher query on the knowledge graph using the given KnowledgeGraphQueryFilter. This method must be called on the MCT. Use QueuedTask.Run.
Syntax

Parameters

queryFilter
The query filter to submit

Return Value

Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
Remarks
Queries are based on the openCypher query language. Addins should call ArcGIS.Core.Data.Realtime.RealtimeCursorBase.WaitForRowsAsync on the returned KnowledgeGraphCursor instance after submitting a search to wait for rows to be returned. Addins can submit null for the query filter (or KnowledgeGraphQueryFilter.QueryText). This will result in the KnowledgeGraphQueryFilter.Default query filter being executed.
Example
Submit a Graph Query
//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
Convert an Open Cypher Query Result to a Selection
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);
  }
});
Call WaitForRowsAsync With Cancellation
//On the QueuedTask...
//and assuming you have established a connection to a knowledge graph
//...
//submit query or search to return a KnowledgeGraphCursor
//using (var kg_rc = kg.SubmitQuery(kg_qf)) {
//using (var kg_rc = kg.SubmitSearch(kg_sf)) {
//...
//wait for rows to be returned from the server
//"auto-cancel" after 20 seconds
var cancel = new CancellationTokenSource(new TimeSpan(0, 0, 20));
//catch TaskCanceledException
try
{
  while (await kg_rc.WaitForRowsAsync(cancel.Token))
  {
    //check for row events
    while (kg_rc.MoveNext())
    {
      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);
        }
      }
    }
  }
}
//Timeout expired
catch (TaskCanceledException tce)
{
  //Handle cancellation as needed
}
cancel.Dispose();
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3.2 or higher.
See Also