SubFields Property (QueryFilter)

In This Topic

Gets or sets a comma (,) delimited string containing the names of fields for which values should be returned by the query.

Syntax

C#
Visual Basic (Declaration)

public string SubFields {get; set;}

Public Property SubFields As String

Remarks

The subfield property requests a minimum set of fields to return values for, by restricting the set of fields for which values are returned you can optimize the performance of the query when using a query filter. Additional values may be returned for fields that the query requires (e.g., ObjectID or Shape fields). Fields not included in the subfields list or required by the query are still present in the rows returned, but are not populated with values. Including all of the fields in the row ensures that the field index position is constant no matter how it was hydrated.

The default setting for subfields is to request values to be returned for all fields. The strings of "*" or "" can be set to return the query to this default. The default of returning all fields should always be used if the intent of the operation is to alter the values of the row and store it.

To set the subfields property to request the values to be returned for the "Name" and "Age" fields a string of "Name, Age" should be provided (white space is optional).

It is not required to set the subfields property if the query filter is to be used in a context where no rows are returned (e.g., Table.Select).

Example

Searching a Table using QueryFilter

public async Task SearchingATable()
{
  try
  {
    await ArcGIS.Desktop.Framework.Threading.Tasks.QueuedTask.Run(() =>
    {
      using (Geodatabase geodatabase = new Geodatabase(new DatabaseConnectionFile(new Uri("path\\to\\sde\\file\\sdefile.sde"))))
      using (Table table = geodatabase.OpenDataset<Table>("EmployeeInfo"))
      {

        QueryFilter queryFilter = new QueryFilter
        {
          WhereClause = "COSTCTRN = 'Information Technology'",
          SubFields = "KNOWNAS, OFFICE, LOCATION",
          PostfixClause = "ORDER BY OFFICE"
        };

        using (RowCursor rowCursor = table.Search(queryFilter, false))
        {
          while (rowCursor.MoveNext())
          {
            using (Row row = rowCursor.Current)
            {
              string location = Convert.ToString(row["LOCATION"]);
              string knownAs = Convert.ToString(row["KNOWNAS"]);
            }
          }
        }
      }
    });
  }
  catch (GeodatabaseFieldException fieldException)
  {
    // One of the fields in the where clause might not exist. There are multiple ways this can be handled:
    // Handle error appropriately
  }
  catch (Exception exception)
  {
    // logger.Error(exception.Message);
  }
}

Use Select or Search with a Spatial Query

//var featSceneLayer = ...;
//var sname = featSceneLayer.Name;
await QueuedTask.Run(() =>
{
  if (!featSceneLayer.HasAssociatedFeatureService)
    return;//no search or select

  //Select all features within the current map view
  var sz = MapView.Active.GetViewSize();
  var map_pt1 = MapView.Active.ClientToMap(new System.Windows.Point(0, sz.Height));
  var map_pt2 = MapView.Active.ClientToMap(new System.Windows.Point(sz.Width, 0));

  //Convert to an envelope
  var temp_env = EnvelopeBuilderEx.CreateEnvelope(map_pt1, map_pt2, MapView.Active.Map.SpatialReference);

  //Project if needed to the layer spatial ref
  SpatialReference sr = null;
  using (var fc = featSceneLayer.GetFeatureClass())
  using (var fdef = fc.GetDefinition())
    sr = fdef.GetSpatialReference();

  var env = GeometryEngine.Instance.Project(temp_env, sr) as Envelope;

  //Set up a query filter
  var sf = new SpatialQueryFilter()
  {
    FilterGeometry = env,
    SpatialRelationship = SpatialRelationship.Intersects,
    SubFields = "*"
  };

  //Select against the feature service
  var select = featSceneLayer.Select(sf);
  if (select.GetCount() > 0)
  {
    //enumerate over the selected features
    using (var rc = select.Search())
    {
      while (rc.MoveNext())
      {
        using (var feature = rc.Current as Feature)
        {
          var oid = feature.GetObjectID();
          //etc.
        }
      }
    }
  }

  MapView.Active.Map.ClearSelection();

});

Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.

Reference

QueryFilter Class
QueryFilter Members

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