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ArcGIS Runtime SDK for .NET

WMS service catalog

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

Connect to a WMS service and show the available layers and sublayers. Layers are shown in a hierarchy. Selecting a group layer will recursively select all sublayers for display.

screenshot

How to use the sample

  1. Open the sample. A hierarchical list of layers and sublayers will appear.
  2. Select a layer to enable it for display. If the layer has any children, the children will also be selected.

How it works

  1. A WmsService is created and loaded.
  2. WmsService has a ServiceInfo property, which is a WmsServiceInfo. WmsServiceInfo has a WmsLayerInfo object for each layer (excluding sublayers) in the LayerInfos collection.
  3. A method is called to recursively discover sublayers for each layer. Layers are wrapped in a view model and added to a list.
    • The view model has a Select method which recursively selects or deselects itself and sublayers.
    • The view model tracks the children and parent of each layer.
  4. Once the layer selection has been updated, another method is called to create a new WmsLayer from a list of selected WmsLayerInfo.

Relevant API

  • WmsLayer(List)
  • WmsLayerInfo
  • WmsService
  • WmsServiceInfo

About the data

The map in this sample shows a weather forecast produced by the U.S. National Weather Service. The map shows fronts, highs, and lows, as well as areas of forecast precipitation. For more information, see the service page.

Tags

OGC, WmsLayer, WmsLayerInfo, WmsService, WmsServiceInfo, web map service

Sample Code

<UserControl
    x:Class="ArcGISRuntime.UWP.Samples.WmsServiceCatalog.WmsServiceCatalog"
    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" />
                </Grid.RowDefinitions>
                <TextBlock Text="Select a WMS layer from the list for display:" Grid.Row="0" />
                <!-- This is a workaround until a proper TreeView is a available for all supported UWP platforms. -->
                <ListBox x:Name="MyDisplayList" SelectionMode="Single"
                         SelectionChanged="MyDisplayList_SelectionChanged_1" Grid.Row="1" />
            </Grid>
        </Border>
    </Grid>
</UserControl>
// Copyright 2017 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.Mapping;
using Esri.ArcGISRuntime.Ogc;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using Windows.UI.Popups;

namespace ArcGISRuntime.UWP.Samples.WmsServiceCatalog
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        "WMS service catalog",
        "Layers",
        "This sample demonstrates how to enable and disable the display of layers discovered from a WMS service.",
        "")]
    public partial class WmsServiceCatalog
    {
        // Hold the URL to the WMS service providing the US NOAA National Weather Service forecast weather chart.
        private readonly Uri _wmsUrl = new Uri(
            "https://idpgis.ncep.noaa.gov/arcgis/services/NWS_Forecasts_Guidance_Warnings/natl_fcst_wx_chart/MapServer/WMSServer?request=GetCapabilities&service=WMS");

        // Hold a list of LayerDisplayVM; this is the ViewModel.
        private ObservableCollection<LayerDisplayVM> _viewModelList = new ObservableCollection<LayerDisplayVM>();

        public WmsServiceCatalog()
        {
            InitializeComponent();

            Initialize();
        }

        private async void Initialize()
        {
            // Apply an imagery basemap to the map.
            MyMapView.Map = new Map(Basemap.CreateDarkGrayCanvasVector());

            // Create the WMS Service.
            WmsService service = new WmsService(_wmsUrl);

            try
            {
                // Load the WMS Service.
                await service.LoadAsync();

                // Get the service info (metadata) from the service.
                WmsServiceInfo info = service.ServiceInfo;

                // Get the list of layer infos.
                foreach (var layerInfo in info.LayerInfos)
                {
                    LayerDisplayVM.BuildLayerInfoList(new LayerDisplayVM(layerInfo, null), _viewModelList);
                }

                // Update the map display based on the viewModel.
                UpdateMapDisplay(_viewModelList);

                // Update the list of layers.
                MyDisplayList.ItemsSource = _viewModelList;
            }
            catch (Exception e)
            {
                await new MessageDialog(e.ToString(), "Error").ShowAsync();
            }
        }

        /// <summary>
        /// Updates the map with the latest layer selection
        /// </summary>
        private void UpdateMapDisplay(ObservableCollection<LayerDisplayVM> displayList)
        {
            // Remove all existing layers.
            MyMapView.Map.OperationalLayers.Clear();

            // Get a list of selected LayerInfos.
            List<WmsLayerInfo> selectedLayers = displayList.Where(vm => vm.IsEnabled).Select(vm => vm.Info).ToList();

            // Return if no layers selected.
            if (!selectedLayers.Any())
            {
                return;
            }

            // Create a new WmsLayer from the selected layers.
            WmsLayer myLayer = new WmsLayer(selectedLayers);

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

        /// <summary>
        /// Takes action once a new layer selection is made.
        /// </summary>
        private void MyDisplayList_SelectionChanged_1(object sender, Windows.UI.Xaml.Controls.SelectionChangedEventArgs e)
        {
            // Deselect removed layers.
            foreach (LayerDisplayVM item in e.RemovedItems)
            {
                item.Select(false);
            }

            // Select added layers.
            foreach (LayerDisplayVM item in e.AddedItems)
            {
                item.Select();
            }

            // Update the map.
            UpdateMapDisplay(_viewModelList);
        }
    }

    /// <summary>
    /// This is a ViewModel class for maintaining the state of a layer selection.
    /// Typically, this would go in a separate file, but it is included here for clarity.
    /// </summary>
    public class LayerDisplayVM
    {
        public WmsLayerInfo Info { get; }

        // True if layer is selected for display.
        public bool IsEnabled { get; set; }

        // Keeps track of how much indentation should be added (to simulate a tree view in a list).
        private int NestLevel
        {
            get
            {
                if (Parent == null)
                {
                    return 0;
                }

                return Parent.NestLevel + 1;
            }
        }

        private List<LayerDisplayVM> Children { get; set; }

        private LayerDisplayVM Parent { get; }

        public LayerDisplayVM(WmsLayerInfo info, LayerDisplayVM parent)
        {
            Info = info;
            Parent = parent;
        }

        // Select this layer and all child layers.
        public void Select(bool isSelected = true)
        {
            IsEnabled = isSelected;
            if (Children == null)
            {
                return;
            }

            foreach (var child in Children)
            {
                child.Select(isSelected);
            }
        }

        // Override ToString to enhance display formatting.
        public override string ToString()
        {
            return new String('\t', NestLevel) + Info.Title;
        }

        public static void BuildLayerInfoList(LayerDisplayVM root, IList<LayerDisplayVM> result)
        {
            // Add the root node to the result list.
            result.Add(root);

            // Initialize the child collection for the root.
            root.Children = new List<LayerDisplayVM>();

            // Recursively add sublayers.
            foreach (WmsLayerInfo layer in root.Info.LayerInfos)
            {
                // Create the view model for the sublayer.
                LayerDisplayVM layerVM = new LayerDisplayVM(layer, root);

                // Add the sublayer to the root's sublayer collection.
                root.Children.Add(layerVM);

                // Recursively add children.
                BuildLayerInfoList(layerVM, result);
            }
        }
    }
}