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ArcGIS Runtime SDK for .NET

Browse WFS layers

This code sample is available for these platforms:
View Sample on GitHub

Browse a WFS service for layers.

Use case

Many GIS scenarios involve accessing a service and discovering which layers should be displayed. For example, a feature service for a city might have layers representing roads, land masses, building footprints, parks, and facilities. A user may choose to only show the road network and parks for a park accessibility analysis.

How to use the sample

A list of layers in the WFS service will be shown. Select a layer to display.

Some WFS services return coordinates in X,Y order, while others return coordinates in lat/long (Y,X) order. If you don't see features rendered or you see features in the wrong location, use the checkbox to change the coordinate order and reload.

How it works

  1. Create a WfsService object with a URL to a WFS feature service.
  2. Obtain a list of WfsLayerInfo from WfsService.ServiceInfo.
  3. When a layer is selected, create a WfsFeatureTable from the WfsLayerInfo.
    • Set the axis order if necessary.
  4. Create a feature layer from the feature table.
  5. Add the feature layer to the map.
    • The sample uses randomly generated symbology, similar to the behavior in ArcGIS Pro.

Relevant API

  • WfsService
  • WfsServiceInfo
  • WfsLayerInfo
  • WfsFeatureTable
  • FeatureLayer
  • WfsFeatureTable.AxisOrder

About the data

This service shows features for downtown Seattle. For additional information, see the underlying service on ArcGIS Online.

Tags

OGC, WFS, feature, web, service, layers, browse, catalog

Sample Code

<UserControl 
    x:Class="ArcGISRuntime.UWP.Samples.BrowseWfsLayers.BrowseWfsLayers"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:esriUI="using:Esri.ArcGISRuntime.UI.Controls">
    <Grid>
        <esriUI:MapView x:Name="MyMapView" />
        <Border Style="{StaticResource BorderStyle}">
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition Height="auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="*" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                </Grid.RowDefinitions>
                <TextBlock Text="Select a WFS layer for display."
                           Grid.Row="0" Margin="5"
                           Foreground="Black" FontWeight="Bold" TextAlignment="Center" />
                <ProgressBar x:Name="LoadingProgressBar"
                             Grid.Row="1"
                             Height="15"
                             IsIndeterminate="True"
                             IsEnabled="True"
                             Margin="0,5,0,5"
                             Visibility="Visible" />
                <ListView x:Name="WfsLayerList" 
                          Grid.Row="2"
                          SelectionMode="Single">
                    <ListView.ItemTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding Title}" />
                        </DataTemplate>
                    </ListView.ItemTemplate>
                </ListView>
                <CheckBox x:Name="AxisOrderSwapCheckbox"
                          Grid.Row="3"
                          Margin="0,5,0,5"
                          Content="Swap coordinate order" />
                <Button x:Name="LoadLayersButton" 
                        Grid.Row="4"
                        Content="Load selected layer"
                        HorizontalAlignment="Stretch"
                        Click="LoadLayers_Clicked"
                        IsEnabled="False" />
            </Grid>
        </Border>
    </Grid>
</UserControl>
// Copyright 2019 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.Ogc;
using Esri.ArcGISRuntime.Symbology;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using Windows.UI.Popups;
using Windows.UI.Xaml;

namespace ArcGISRuntime.UWP.Samples.BrowseWfsLayers
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        "Browse a WFS service for layers",
        "Layers",
        "Browse for layers in a WFS service.",
        "")]
    public partial class BrowseWfsLayers
    {
        // URL to the WFS service.
        private const string ServiceUrl = "https://dservices2.arcgis.com/ZQgQTuoyBrtmoGdP/arcgis/services/Seattle_Downtown_Features/WFSServer?service=wfs&request=getcapabilities";

        public BrowseWfsLayers()
        {
            InitializeComponent();
            Initialize();
        }

        private async void Initialize()
        {
            // Create the map with imagery basemap.
            MyMapView.Map = new Map(Basemap.CreateImagery());

            // Create the WFS service.
            WfsService service = new WfsService(new Uri(ServiceUrl));

            // Load the WFS service.
            await service.LoadAsync();

            // Get the service metadata.
            WfsServiceInfo serviceInfo = service.ServiceInfo;

            // Get a reversed list of available layers.
            IEnumerable<WfsLayerInfo> layerListReversed = serviceInfo.LayerInfos.Reverse();

            // Show the layers in the UI.
            WfsLayerList.ItemsSource = layerListReversed;

            // Update the UI.
            LoadingProgressBar.Visibility = Visibility.Collapsed;
            LoadLayersButton.IsEnabled = true;
        }

        private async void LoadLayers_Clicked(object sender, RoutedEventArgs e)
        {
            // Skip if nothing selected.
            if (WfsLayerList.SelectedItems.Count < 1)
            {
                return;
            }

            // Show the progress bar.
            LoadingProgressBar.Visibility = Visibility.Visible;

            // Clear the existing layers.
            MyMapView.Map.OperationalLayers.Clear();

            try
            {
                // Get the selected WFS layer.
                WfsLayerInfo selectedLayerInfo = (WfsLayerInfo)WfsLayerList.SelectedItems[0];

                // Create the WFS feature table.
                WfsFeatureTable table = new WfsFeatureTable(selectedLayerInfo);
                
                // Set the feature request mode to manual - only manual is supported at v100.5.
                // In this mode, you must manually populate the table - panning and zooming won't request features automatically.
                table.FeatureRequestMode = FeatureRequestMode.ManualCache;

                // Set the axis order based on the UI.
                if (AxisOrderSwapCheckbox.IsChecked == true)
                {
                    table.AxisOrder = OgcAxisOrder.Swap;
                }
                else
                {
                    table.AxisOrder = OgcAxisOrder.NoSwap;
                }

                // Populate the WFS table.
                await table.PopulateFromServiceAsync(new QueryParameters(), false, null);

                // Create a feature layer from the WFS table.
                FeatureLayer wfsFeatureLayer = new FeatureLayer(table);

                // Choose a renderer for the layer based on the table.
                wfsFeatureLayer.Renderer = GetRandomRendererForTable(table) ?? wfsFeatureLayer.Renderer;

                // Add the layer to the map.
                MyMapView.Map.OperationalLayers.Add(wfsFeatureLayer);

                // Zoom to the extent of the selected layer.
                await MyMapView.SetViewpointGeometryAsync(selectedLayerInfo.Extent, 50);
            }
            catch (Exception exception)
            {
                Debug.WriteLine(exception);
                await new MessageDialog(exception.ToString(), "Failed to load layer.").ShowAsync();
            }
            finally
            {
                // Hide the progress bar.
                LoadingProgressBar.Visibility = Visibility.Collapsed;
            }
        }

        #region Random symbology
        // Random number generator used to generate random symbology.
        private static readonly Random _rand = new Random();

        private Renderer GetRandomRendererForTable(FeatureTable table)
        {
            switch (table.GeometryType)
            {
                case GeometryType.Point:
                case GeometryType.Multipoint:
                    return new SimpleRenderer(new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Circle, GetRandomColor(), 4));
                case GeometryType.Polygon:
                case GeometryType.Envelope:
                    return new SimpleRenderer(new SimpleFillSymbol(SimpleFillSymbolStyle.Solid, GetRandomColor(180), null));
                case GeometryType.Polyline:
                    return new SimpleRenderer(new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, GetRandomColor(), 1));
            }

            return null;
        }

        private Color GetRandomColor(int alpha = 255)
        {
            return Color.FromArgb(alpha, _rand.Next(0, 255), _rand.Next(0, 255), _rand.Next(0, 255));
        }
        #endregion Random symbology
    }
}