ServiceFeatureTableManualCache.cs

// 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.UI.Controls;
using Foundation;
using System;
using UIKit;

namespace ArcGISRuntimeXamarin.Samples.ServiceFeatureTableManualCache
{
    [Register("ServiceFeatureTableManualCache")]
    public class ServiceFeatureTableManualCache : UIViewController
    {
        // Constant holding offset where the MapView control should start
        private const int yPageOffset = 60;

        // Create and hold reference to the used MapView
        private MapView _myMapView = new MapView();

        private ServiceFeatureTable _incidentsFeatureTable;

        public ServiceFeatureTableManualCache()
        {
            Title = "Service feature table (manual cache)";
        }

        public override void ViewDidLayoutSubviews()
        {
            base.ViewDidLayoutSubviews();

            // 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(
                -13630484, 4545415, SpatialReferences.WebMercator);
            myMap.InitialViewpoint = new Viewpoint(initialLocation, 500000);

            // Create uri to the used feature service
            var serviceUri = new Uri(
               "https://sampleserver6.arcgisonline.com/arcgis/rest/services/SF311/FeatureServer/0");

            // Create feature table for the incident feature service
            _incidentsFeatureTable = new ServiceFeatureTable(serviceUri);

            // Define the request mode
            _incidentsFeatureTable.FeatureRequestMode = FeatureRequestMode.ManualCache;

            // When feature table is loaded, populate data
            _incidentsFeatureTable.LoadStatusChanged += OnLoadedPopulateData;

            // Create FeatureLayer that uses the created table
            FeatureLayer incidentsFeatureLayer = new FeatureLayer(_incidentsFeatureTable);

            // Add created layer to the map
            myMap.OperationalLayers.Add(incidentsFeatureLayer);

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

        private async void OnLoadedPopulateData(object sender, Esri.ArcGISRuntime.LoadStatusEventArgs e)
        {
            // If layer isn't loaded, do nothing
            if (e.Status != Esri.ArcGISRuntime.LoadStatus.Loaded)
                return;

            // Create new query object that contains parameters to query specific request types
            QueryParameters queryParameters = new QueryParameters()
            {
                WhereClause = "req_Type = 'Tree Maintenance or Damage'"
            };

            // Create list of the fields that are returned from the service
            var outputFields = new string[] { "*" };

            // Populate feature table with the data based on query
            await _incidentsFeatureTable.PopulateFromServiceAsync(queryParameters, true, outputFields);
        }

        private void CreateLayout()
        {
            // Setup the visual frame for the MapView
            _myMapView.Frame = new CoreGraphics.CGRect(
                0, yPageOffset, View.Bounds.Width, View.Bounds.Height - yPageOffset);

            // Add MapView to the page
            View.AddSubviews(_myMapView);
        }
    }
}