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Feature Class

Represents a row in a FeatureTable
Inheritance Hierarchy

Namespace:  Esri.ArcGISRuntime.Data
Assembly:  Esri.ArcGISRuntime (in Esri.ArcGISRuntime.dll) Version: 100.7.0.0
Syntax
C#
public class Feature : GeoElement

The Feature type exposes the following members.

Properties
  NameDescription
Public propertyCode exampleAttributes
Gets the attributes of this GeoElement as a collection of name/value pairs.
(Inherited from GeoElement.)
Public propertyCode exampleFeatureTable
Gets the FeatureTable that this feature belongs to
Public propertyGeometry
Gets or sets the Geometry of the feature.
(Overrides GeoElementGeometry.)
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Methods
  NameDescription
Public methodGetAttributeValue(String)
Looks up attribute by name and returns its current value.
Public methodGetAttributeValue(Field)
Looks up attribute by Field and returns its current value.
Public methodCode exampleRefresh
Resets the attributes and geometry to the values in the data source
Public methodSetAttributeValue(String, Object)
Looks up attribute by name and updates attribute to the specified value.
Public methodSetAttributeValue(Field, Object)
Looks up attribute by Field and updates attribute to the specified value.
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Examples

Android

Example Name: FeatureLayerQuery

Find features in a feature table which match an SQL query.

Code example screen shot.

C#
// Copyright 2016 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 Android.App;
using Android.OS;
using Android.Widget;
using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.UI.Controls;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Threading.Tasks;
using Android.Text;

namespace ArcGISRuntime.Samples.FeatureLayerQuery
{
    [Activity (ConfigurationChanges=Android.Content.PM.ConfigChanges.Orientation | Android.Content.PM.ConfigChanges.ScreenSize)]
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        "Feature layer query",
        "Data",
        "Query a feature layer via a feature table.",
        "The sample provides a search bar on the top, where you can input the name of a US State. When you hit search the app performs a query on the feature table and based on the result either highlights the state geometry or provides an error.")]
    public class FeatureLayerQuery : Activity
    {
        // Create reference to service of US States
        private string _statesUrl = "https://services.arcgis.com/jIL9msH9OI208GCb/arcgis/rest/services/USA_Daytime_Population_2016/FeatureServer/0";

        // Hold a reference to the map view
        private MapView _myMapView;

        // Create globally available text box for easy referencing
        private EditText _queryTextBox;

        // Create globally available feature table for easy referencing
        private ServiceFeatureTable _featureTable;

        // Create globally available feature layer for easy referencing
        private FeatureLayer _featureLayer;

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);
            Title = "Feature layer  query";

            // Create the UI, setup the control references and execute initialization
            CreateLayout();
            Initialize();
        }

        private void Initialize()
        {
            // Create new Map with basemap
            Map myMap = new Map(Basemap.CreateTopographic());

            // Create and set initial map location
            MapPoint initialLocation = new MapPoint(
                -11000000, 5000000, SpatialReferences.WebMercator);
            myMap.InitialViewpoint = new Viewpoint(initialLocation, 100000000);

            // Create feature table using a url
            _featureTable = new ServiceFeatureTable(new Uri(_statesUrl));

            // Create feature layer using this feature table
            _featureLayer = new FeatureLayer(_featureTable)
            {
                // Set the Opacity of the Feature Layer
                Opacity = 0.6,
                // Work around service setting
                MaxScale = 10
            };

            // Create a new renderer for the States Feature Layer.
            SimpleLineSymbol lineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, Color.Black, 1);
            SimpleFillSymbol fillSymbol = new SimpleFillSymbol(SimpleFillSymbolStyle.Solid, Color.Transparent, lineSymbol);

            // Set States feature layer renderer
            _featureLayer.Renderer = new SimpleRenderer(fillSymbol);

            // Add feature layer to the map
            myMap.OperationalLayers.Add(_featureLayer);

            // Update the selection color
            _myMapView.SelectionProperties.Color = Color.Cyan;

            // Assign the map to the MapView
            _myMapView.Map = myMap;
        }

        private async void OnQueryClicked(object sender, EventArgs e)
        {
            // Remove any previous feature selections that may have been made
            _featureLayer.ClearSelection();

            // Begin query process
            await QueryStateFeature(_queryTextBox.Text);
        }

        private async Task QueryStateFeature(string stateName)
        {
            // Create dialog to display alert information
            AlertDialog.Builder alert = new AlertDialog.Builder(this);

            try
            {
                // Create a query parameters that will be used to Query the feature table
                QueryParameters queryParams = new QueryParameters
                {

                    // Construct and assign the where clause that will be used to query the feature table
                    WhereClause = "upper(STATE_NAME) LIKE '%" + stateName.Trim().ToUpper() + "%'"
                };

                // Query the feature table
                FeatureQueryResult queryResult = await _featureTable.QueryFeaturesAsync(queryParams);

                // Cast the QueryResult to a List so the results can be interrogated.
                List<Feature> features = queryResult.ToList();

                if (features.Any())
                {
                    // Create an envelope.
                    EnvelopeBuilder envBuilder = new EnvelopeBuilder(SpatialReferences.WebMercator);

                    // Loop over each feature from the query result.
                    foreach (Feature feature in features)
                    {
                        // Add the extent of each matching feature to the envelope.
                        envBuilder.UnionOf(feature.Geometry.Extent);

                        // Select each feature.
                        _featureLayer.SelectFeature(feature);
                    }

                    // Zoom to the extent of the selected feature(s).
                    await _myMapView.SetViewpointGeometryAsync(envBuilder.ToGeometry(), 50);
                }
                else
                {
                    alert.SetTitle("State Not Found!");
                    alert.SetMessage("Add a valid state name.");
                    alert.Show();
                }
            }
            catch (Exception ex)
            {
                alert.SetTitle("Sample Error");
                alert.SetMessage(ex.Message);
                alert.Show();
            }
        }

        private void CreateLayout()
        {
            // Create a new vertical layout for the app
            LinearLayout layout = new LinearLayout(this) { Orientation = Orientation.Vertical };

            // Create new Text box that will take the query parameter
            _queryTextBox = new EditText(this)
            {
                InputType = InputTypes.ClassText | InputTypes.TextVariationNormal
            };
            _queryTextBox.SetMaxLines(1);

            // Create Button that will start the Feature Query
            Button queryButton = new Button(this)
            {
                Text = "Query"
            };
            queryButton.Click += OnQueryClicked;

            // Create and add a help label
            TextView helpLabel = new TextView(this)
            {
                Text = "Enter the name of a state, then press 'Query' to search."
            };
            layout.AddView(helpLabel);

            // Add TextBox to the layout
            layout.AddView(_queryTextBox);

            // Add Button to the layout
            layout.AddView(queryButton);

            // Add the map view to the layout
            _myMapView = new MapView(this);
            layout.AddView(_myMapView);

            // Show the layout in the app
            SetContentView(layout);
        }
    }
}
Examples

Xamarin Forms Android

Example Name: FeatureLayerQuery

Find features in a feature table which match an SQL query.

Code example screen shot.

C#
// Copyright 2016 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 Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Symbology;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Xamarin.Forms;
using Colors = System.Drawing.Color;

namespace ArcGISRuntime.Samples.FeatureLayerQuery
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        "Feature layer query",
        "Data",
        "Query a feature layer via a feature table.",
        "The sample provides a search bar on the top, where you can input the name of a US State. When you hit search the app performs a query on the feature table and based on the result either highlights the state geometry or provides an error.")]
    public partial class FeatureLayerQuery : ContentPage
    {
        // Create reference to service of US States
        private string _statesUrl = "https://sampleserver6.arcgisonline.com/arcgis/rest/services/USA/MapServer/2";

        // Create globally available feature table for easy referencing
        private ServiceFeatureTable _featureTable;

        // Create globally available feature layer for easy referencing
        private FeatureLayer _featureLayer;

        public FeatureLayerQuery()
        {
            InitializeComponent();

            // Create the UI, setup the control references and execute initialization
            Initialize();
        }

        private void Initialize()
        {
            // Create new Map with basemap
            Map myMap = new Map(Basemap.CreateTopographic());

            // Create and set initial map location
            MapPoint initialLocation = new MapPoint(
                -11000000, 5000000, SpatialReferences.WebMercator);
            myMap.InitialViewpoint = new Viewpoint(initialLocation, 100000000);

            // Create feature table using a url
            _featureTable = new ServiceFeatureTable(new Uri(_statesUrl));

            // Create feature layer using this feature table
            _featureLayer = new FeatureLayer(_featureTable)
            {
                // Set the Opacity of the Feature Layer
                Opacity = 0.6,
                // Work around service setting
                MaxScale = 10
            };

            // Create a new renderer for the States Feature Layer.
            SimpleLineSymbol lineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, Colors.Black, 1);
            SimpleFillSymbol fillSymbol = new SimpleFillSymbol(SimpleFillSymbolStyle.Solid, Colors.Transparent, lineSymbol);

            // Set States feature layer renderer
            _featureLayer.Renderer = new SimpleRenderer(fillSymbol);

            // Add feature layer to the map
            myMap.OperationalLayers.Add(_featureLayer);

            // Set the selection color
            myMapView.SelectionProperties.Color = Color.Cyan;

            // Assign the map to the MapView
            myMapView.Map = myMap;
        }

        private async void OnQueryClicked(object sender, EventArgs e)
        {
            // Remove any previous feature selections that may have been made
            _featureLayer.ClearSelection();

            // Begin query process
            await QueryStateFeature(queryEntry.Text);
        }

        private async Task QueryStateFeature(string stateName)
        {
            try
            {
                // Create a query parameters that will be used to Query the feature table
                QueryParameters queryParams = new QueryParameters();

                // Trim whitespace on the state name to prevent broken queries
                string formattedStateName = stateName.Trim().ToUpper();

                // Construct and assign the where clause that will be used to query the feature table
                queryParams.WhereClause = "upper(STATE_NAME) LIKE '%" + formattedStateName + "%'";

                // Query the feature table
                FeatureQueryResult queryResult = await _featureTable.QueryFeaturesAsync(queryParams);

                // Cast the QueryResult to a List so the results can be interrogated.
                List<Feature> features = queryResult.ToList();

                if (features.Any())
                {
                    // Create an envelope.
                    EnvelopeBuilder envBuilder = new EnvelopeBuilder(SpatialReferences.WebMercator);

                    // Loop over each feature from the query result.
                    foreach (Feature feature in features)
                    {
                        // Add the extent of each matching feature to the envelope.
                        envBuilder.UnionOf(feature.Geometry.Extent);

                        // Select each feature.
                        _featureLayer.SelectFeature(feature);
                    }

                    // Zoom to the extent of the selected feature(s).
                    await myMapView.SetViewpointGeometryAsync(envBuilder.ToGeometry(), 50);
                }
                else
                {
                    await Application.Current.MainPage.DisplayAlert("State Not Found!", "Add a valid state name.", "OK");
                }
            }
            catch (Exception)
            {
                await Application.Current.MainPage.DisplayAlert("Sample error", "An error occurred", "OK");
            }
        }
    }
}
XAML
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"             
             xmlns:esriUI="clr-namespace:Esri.ArcGISRuntime.Xamarin.Forms;assembly=Esri.ArcGISRuntime.Xamarin.Forms"
             xmlns:mapping="clr-namespace:Esri.ArcGISRuntime.Mapping;assembly=Esri.ArcGISRuntime" 
             x:Class="ArcGISRuntime.Samples.FeatureLayerQuery.FeatureLayerQuery">
  <Grid>
    <Grid.RowDefinitions>
      <RowDefinition Height="auto" />
      <RowDefinition Height="*" />
    </Grid.RowDefinitions>
    <StackLayout Orientation="Vertical">
      <Entry x:Name="queryEntry" Text="New York"/>
      <Button Text="Query" Clicked="OnQueryClicked"/>
    </StackLayout>
    <esriUI:MapView x:Name="myMapView"  Grid.Row="1"/>
  </Grid>
</ContentPage>
See Also
Additional Examples
Hyperlink to ExampleDescription
AddFeaturesAdd features to a feature layer.
AnalyzeViewshedCalculate a viewshed using a geoprocessing service, in this case showing what parts of a landscape are visible from points on mountainous terrain.
ClosestFacilityStaticFind routes from several locations to the respective closest facility.
CreateFeatureCollectionLayerCreate a Feature Collection Layer from a Feature Collection Table, and add it to a map.
DeleteFeaturesDelete features from an online feature service.
EditAndSyncFeaturesSynchronize offline edits with a feature service.
EditFeatureAttachmentsAdd, delete, and download attachments for features from a service.
FeatureLayerQueryFind features in a feature table which match an SQL query.
GeodatabaseTransactionsThis sample demonstrates how to manage edits to a local geodatabase inside of transactions.
ListGeodatabaseVersionsThis sample calls a custom GeoprocessingTask to get a list of available versions for an enterprise geodatabase. The task returns a table of geodatabase version information, which is displayed in the app as a list.
ListRelatedFeaturesList features related to the selected feature.
MapImageSublayerQueryFind features in a sublayer based on attributes and location.
SceneLayerSelectionIdentify GeoElements in a scene layer.
TraceUtilityNetworkDiscover connected features in a utility network using connected, subnetwork, upstream, and downstream traces.
UpdateAttributesUpdate feature attributes in an online feature service.
UpdateGeometriesUpdate a feature's location in an online feature service.