ArcGIS Pro 2.6 API Reference Guide
Select(QueryFilter,SelectionOption) Method
Example 

ArcGIS.Core.Data Namespace > Selection Class : Select(QueryFilter,SelectionOption) Method
A filter used when querying the selection. This argument is optional. If unset or set to null, a default query filter will be used.
Specifies the content of the Selection.
Creates a selection of specific rows in this Selection that satisfy the criteria set in the queryFilter. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
Public Function Select( _
   Optional ByVal queryFilter As QueryFilter, _
   Optional ByVal selectionOption As SelectionOption _
) As Selection

Parameters

queryFilter
A filter used when querying the selection. This argument is optional. If unset or set to null, a default query filter will be used.
selectionOption
Specifies the content of the Selection.

Return Value

A new Selection instance that satisfies the criteria set in queryFilter and selectionOption.
Exceptions
ExceptionDescription
If queryFilter is an instance of SpatialQueryFilter, either both the 'FilterGeometry' and 'SpatialRelationship' properties are set or both are not set. Otherwise, an ArgumentException will be raised.
A geodatabase-related exception has occurred.
Example
/*

   Copyright 2018 Esri

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

   See the License for the specific language governing permissions and
   limitations under the License.

*/
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using ArcGIS.Core.Data;
using ArcGIS.Core.Geometry;
using ArcGIS.Desktop.Framework.Threading.Tasks;

namespace SDKExamples.GeodatabaseSDK
{
  /// <summary>
  /// Illustrates how to select from a Selection object.
  /// </summary>
  /// 
  /// <remarks>
  /// <para>
  /// While it is true classes that are derived from the <see cref="ArcGIS.Core.CoreObjectsBase"/> super class 
  /// consumes native resources (e.g., <see cref="ArcGIS.Core.Data.Geodatabase"/> or <see cref="ArcGIS.Core.Data.FeatureClass"/>), 
  /// you can rest assured that the garbage collector will properly dispose of the unmanaged resources during 
  /// finalization.  However, there are certain workflows that require a <b>deterministic</b> finalization of the 
  /// <see cref="ArcGIS.Core.Data.Geodatabase"/>.  Consider the case of a file geodatabase that needs to be deleted 
  /// on the fly at a particular moment.  Because of the <b>indeterministic</b> nature of garbage collection, we can't
  /// count on the garbage collector to dispose of the Geodatabase object, thereby removing the <b>lock(s)</b> at the  
  /// moment we want. To ensure a deterministic finalization of important native resources such as a 
  /// <see cref="ArcGIS.Core.Data.Geodatabase"/> or <see cref="ArcGIS.Core.Data.FeatureClass"/>, you should declare 
  /// and instantiate said objects in a <b>using</b> statement.  Alternatively, you can achieve the same result by 
  /// putting the object inside a try block and then calling Dispose() in a finally block.
  /// </para>
  /// <para>
  /// In general, you should always call Dispose() on the following types of objects: 
  /// </para>
  /// <para>
  /// - Those that are derived from <see cref="ArcGIS.Core.Data.Datastore"/> (e.g., <see cref="ArcGIS.Core.Data.Geodatabase"/>).
  /// </para>
  /// <para>
  /// - Those that are derived from <see cref="ArcGIS.Core.Data.Dataset"/> (e.g., <see cref="ArcGIS.Core.Data.Table"/>).
  /// </para>
  /// <para>
  /// - <see cref="ArcGIS.Core.Data.RowCursor"/> and <see cref="ArcGIS.Core.Data.RowBuffer"/>.
  /// </para>
  /// <para>
  /// - <see cref="ArcGIS.Core.Data.Row"/> and <see cref="ArcGIS.Core.Data.Feature"/>.
  /// </para>
  /// <para>
  /// - <see cref="ArcGIS.Core.Data.Selection"/>.
  /// </para>
  /// <para>
  /// - <see cref="ArcGIS.Core.Data.VersionManager"/> and <see cref="ArcGIS.Core.Data.Version"/>.
  /// </para>
  /// </remarks>    
  public class SelectionSelect
  {
    /// <summary>
    /// In order to illustrate that Geodatabase calls have to be made on the MCT
    /// </summary>
    /// <returns></returns>
    public async Task SelectionSelectAsync()
    {
      await QueuedTask.Run(() => MainMethodCode());
    }

    public void MainMethodCode()
    {
      using (Geodatabase fileGeodatabase = new Geodatabase(new FileGeodatabaseConnectionPath(new Uri(@"C:\Data\LocalGovernment.gdb"))))
      using (Table table                 = fileGeodatabase.OpenDataset<Table>("EmployeeInfo"))
      using (Selection selection         = table.Select(null, SelectionType.ObjectID, SelectionOption.Normal))
      {
        QueryFilter queryFilter = new QueryFilter{WhereClause = "COSTCTRN = 'Finance'"};

        // An existing selection can be further filtered to get another selection as below.
        using (Selection newSelection = selection.Select(queryFilter))
        {
        }
      }
     
      // Opening a Non-Versioned SQL Server instance.

      DatabaseConnectionProperties connectionProperties = new DatabaseConnectionProperties(EnterpriseDatabaseType.SQLServer)
      {
        AuthenticationMode = AuthenticationMode.DBMS,

        // Where testMachine is the machine where the instance is running and testInstance is the name of the SqlServer instance.
        Instance = @"testMachine\testInstance",

        // Provided that a database called LocalGovernment has been created on the testInstance and geodatabase has been enabled on the database.
        Database = "LocalGovernment",

        // Provided that a login called gdb has been created and corresponding schema has been created with the required permissions.
        User     = "gdb",
        Password = "password",
        Version  = "dbo.DEFAULT"
      };
      
      using (Geodatabase geodatabase   = new Geodatabase(connectionProperties))
      using (FeatureClass featureClass = geodatabase.OpenDataset<FeatureClass>("LocalGovernment.GDB.SchoolBoundary"))
      {
        QueryFilter filter = new QueryFilter { WhereClause = "DISTRCTNAME = 'Indian Prairie School District 204'" };

        // The following can be used to find one record out of the selection which will satisfy a clause.
        QueryFilter areaFilter = new QueryFilter { WhereClause = "SCHOOLAREA > 0.5" };

        using (Selection indianPrairieSelection                = featureClass.Select(filter, SelectionType.ObjectID, SelectionOption.Normal))
        using (Selection selectionWithOneSchoolWithDesiredArea = indianPrairieSelection.Select(areaFilter, SelectionOption.OnlyOne))
        {
          // Similar to the Table.Select, one can get an empty selection using the Empty Option.
          using (Selection emptySelection = indianPrairieSelection.Select(areaFilter, SelectionOption.Empty))
          {
          }

          // Using SpatialQueryFilter with Selection.Select.
          SpatialQueryFilter spatialQueryFilter = new SpatialQueryFilter
          {
            FilterGeometry = new PolygonBuilder(new List<Coordinate2D>
            {
              new Coordinate2D(1021880, 1867396),
              new Coordinate2D(1028223, 1870705),
              new Coordinate2D(1031165, 1866844),
              new Coordinate2D(1025373, 1860501),
              new Coordinate2D(1021788, 1863810)
            }).ToGeometry(),

            SpatialRelationship = SpatialRelationship.Intersects
          };

          using (Selection spatialSelection = indianPrairieSelection.Select(spatialQueryFilter))
          {
          }
        }
      }
    }
  }
}
Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

See Also

Reference

Selection Class
Selection Members