Automatic default WMS Layer

MapControl/Shared/WmsImageLayer.cs

@@ -19,6 +19,9 @@ using System.Windows.Media;
 
 namespace MapControl
 {
+    /// <summary>
+    /// Displays a single map image from a Web Map Service (WMS).
+    /// </summary>
     public partial class WmsImageLayer : MapImageLayer
     {
         public static readonly DependencyProperty ServiceUriProperty = DependencyProperty.Register(
@@ -27,7 +30,7 @@ namespace MapControl
 
         public static readonly DependencyProperty LayersProperty = DependencyProperty.Register(
             nameof(Layers), typeof(string), typeof(WmsImageLayer),
-            new PropertyMetadata(string.Empty, async (o, e) => await ((WmsImageLayer)o).UpdateImageAsync()));
+            new PropertyMetadata(null, async (o, e) => await ((WmsImageLayer)o).UpdateImageAsync()));
 
         public static readonly DependencyProperty StylesProperty = DependencyProperty.Register(
             nameof(Styles), typeof(string), typeof(WmsImageLayer),
@@ -37,24 +40,36 @@ namespace MapControl
             nameof(Format), typeof(string), typeof(WmsImageLayer),
             new PropertyMetadata("image/png", async (o, e) => await ((WmsImageLayer)o).UpdateImageAsync()));
 
+        /// <summary>
+        /// The base request URL. 
+        /// </summary>
         public Uri ServiceUri
         {
             get { return (Uri)GetValue(ServiceUriProperty); }
             set { SetValue(ServiceUriProperty, value); }
         }
 
+        /// <summary>
+        /// Comma-separated list of Layer names to be displayed. If not set, the first Layer is displayed.
+        /// </summary>
         public string Layers
         {
             get { return (string)GetValue(LayersProperty); }
             set { SetValue(LayersProperty, value); }
         }
 
+        /// <summary>
+        /// Comma-separated list of requested styles. Default is an empty string.
+        /// </summary>
         public string Styles
         {
             get { return (string)GetValue(StylesProperty); }
             set { SetValue(StylesProperty, value); }
         }
 
+        /// <summary>
+        /// Requested image format. Default is image/png.
+        /// </summary>
         public string Format
         {
             get { return (string)GetValue(FormatProperty); }
@@ -64,36 +79,19 @@ namespace MapControl
         /// <summary>
         /// Gets a list of all layer names returned by a GetCapabilities response.
         /// </summary>
-        public async Task<List<string>> GetLayerNamesAsync()
+        public async Task<IEnumerable<string>> GetLayerNamesAsync()
         {
-            List<string> layerNames = null;
+            IEnumerable<string> layerNames = null;
+            var capabilities = await GetCapabilities();
 
-            if (ServiceUri != null)
+            if (capabilities != null)
             {
-                var uri = GetRequestUri("GetCapabilities").Replace(" ", "%20");
+                var ns = capabilities.Name.Namespace;
 
-                try
+                layerNames = capabilities
-                {
+                    .Descendants(ns + "Layer")
-                    XElement capabilities;
+                    .Select(e => e.Element(ns + "Name")?.Value)
-
+                    .Where(n => !string.IsNullOrEmpty(n));
-                    using (var stream = await ImageLoader.HttpClient.GetStreamAsync(uri))
-                    {
-                        capabilities = XDocument.Load(stream).Root;
-                    }
-
-                    var ns = capabilities.Name.Namespace;
-
-                    layerNames = capabilities
-                        .Descendants(ns + "Layer")
-                        .Where(e => e.Attribute("queryable")?.Value == "1")
-                        .Select(e => e.Element(ns + "Name")?.Value)
-                        .Where(n => !string.IsNullOrEmpty(n))
-                        .ToList();
-                }
-                catch (Exception ex)
-                {
-                    Debug.WriteLine("WmsImageLayer: {0}: {1}", uri, ex.Message);
-                }
             }
 
             return layerNames;
@@ -104,6 +102,13 @@ namespace MapControl
         /// </summary>
         protected override async Task<ImageSource> GetImageAsync()
         {
+            if (Layers == null && // get first Layer
+                ServiceUri != null &&
+                ServiceUri.ToString().IndexOf("LAYERS=", StringComparison.OrdinalIgnoreCase) < 0)
+            {
+                Layers = (await GetLayerNamesAsync())?.FirstOrDefault() ?? "";
+            }
+
             var uri = GetImageUri();
 
             return uri != null
@@ -170,5 +175,31 @@ namespace MapControl
 
             return uri + "REQUEST=" + request;
         }
+
+        private async Task<XElement> GetCapabilities()
+        {
+            XElement capabilities = null;
+
+            if (ServiceUri != null)
+            {
+                var uri = GetRequestUri("GetCapabilities").Replace(" ", "%20");
+
+                try
+                {
+                    using (var stream = await ImageLoader.HttpClient.GetStreamAsync(uri))
+                    {
+                        capabilities = XDocument.Load(stream).Root;
+                    }
+
+                    var ns = capabilities.Name.Namespace;
+                }
+                catch (Exception ex)
+                {
+                    Debug.WriteLine("WmsImageLayer: {0}: {1}", uri, ex.Message);
+                }
+            }
+
+            return capabilities;
+        }
     }
 }

SampleApps/Shared/MapLayers.cs

@@ -21,7 +21,13 @@ namespace ViewModel
         {
             {
                 "OpenStreetMap",
-                MapTileLayer.OpenStreetMapTileLayer
+                new MapTileLayer
+                {
+                    SourceName = "OpenStreetMap",
+                    Description = "© [OpenStreetMap Contributors](http://www.openstreetmap.org/copyright)",
+                    TileSource = new TileSource { UriFormat = "https://{c}.tile.openstreetmap.org/{z}/{x}/{y}.png" },
+                    MaxZoomLevel = 19
+                }
             },
             {
                 "OpenStreetMap German",
@@ -29,7 +35,7 @@ namespace ViewModel
                 {
                     SourceName = "OpenStreetMap German",
                     Description = "© [OpenStreetMap contributors](http://www.openstreetmap.org/copyright)",
-                    TileSource = new TileSource { UriFormat = "http://{c}.tile.openstreetmap.de/tiles/osmde/{z}/{x}/{y}.png" },
+                    TileSource = new TileSource { UriFormat = "https://{c}.tile.openstreetmap.de/tiles/osmde/{z}/{x}/{y}.png" },
                     MaxZoomLevel = 19
                 }
             },
@@ -53,16 +59,6 @@ namespace ViewModel
                     MaxZoomLevel = 18
                 }
             },
-            {
-                "Seamarks",
-                new MapTileLayer
-                {
-                    SourceName = "OpenSeaMap",
-                    TileSource = new TileSource { UriFormat = "http://tiles.openseamap.org/seamark/{z}/{x}/{y}.png" },
-                    MinZoomLevel = 9,
-                    MaxZoomLevel = 18
-                }
-            },
             {
                 "Bing Maps Road",
                 new BingMapsTileLayer
@@ -100,17 +96,7 @@ namespace ViewModel
                 new WmsImageLayer
                 {
                     Description = "© [terrestris GmbH & Co. KG](http://ows.terrestris.de/)\nData © [OpenStreetMap contributors](http://www.openstreetmap.org/copyright)",
-                    ServiceUri = new Uri("http://ows.terrestris.de/osm/service"),
+                    ServiceUri = new Uri("http://ows.terrestris.de/osm/service")
-                    Layers = "OSM-WMS"
-                }
-            },
-            {
-                "OpenStreetMap TOPO WMS",
-                new WmsImageLayer
-                {
-                    Description = "© [terrestris GmbH & Co. KG](http://ows.terrestris.de/)\nData © [OpenStreetMap contributors](http://www.openstreetmap.org/copyright)",
-                    ServiceUri = new Uri("http://ows.terrestris.de/osm/service"),
-                    Layers = "TOPO-OSM-WMS"
                 }
             },
             {
@@ -118,8 +104,7 @@ namespace ViewModel
                 new WmsImageLayer
                 {
                     Description = "© [BKG](https://gdz.bkg.bund.de/index.php/default/webdienste/topplus-produkte/wms-topplusopen-mit-layer-fur-normalausgabe-und-druck-wms-topplus-open.html)",
-                    ServiceUri = new Uri("https://sgx.geodatenzentrum.de/wms_topplus_open"),
+                    ServiceUri = new Uri("https://sgx.geodatenzentrum.de/wms_topplus_open")
-                    Layers = "web"
                 }
             },
             {
@@ -132,9 +117,19 @@ namespace ViewModel
                 }
             },
             {
-                "SevenCs ChartServer",
+                "SevenCs ChartServer WMS",
                 new ChartServerLayer()
             },
+            {
+                "Seamarks",
+                new MapTileLayer
+                {
+                    SourceName = "OpenSeaMap",
+                    TileSource = new TileSource { UriFormat = "http://tiles.openseamap.org/seamark/{z}/{x}/{y}.png" },
+                    MinZoomLevel = 9,
+                    MaxZoomLevel = 18
+                }
+            },
         };
 
         private string currentMapLayerName = "OpenStreetMap";
@@ -167,10 +162,9 @@ namespace ViewModel
             "Stamen Terrain",
             "Stamen Toner Light",
             "OpenStreetMap WMS",
-            "OpenStreetMap TOPO WMS",
             "TopPlusOpen WMS",
             "TopPlusOpen WMTS",
-            "SevenCs ChartServer",
+            "SevenCs ChartServer WMS",
         };
 
         public MapLayers()