await layer.LoadAsync(); invalid response | ArcGIS DevLab; Load an item from ArcGIS Online

Question

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So I am doing some excercises in the DevLab from the ArcGIS developer platform. I did an excercise in which you load a layer from the ArcGIS Online portal. Their example code is the following (it works like a charm);

using System;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Portal;
namespace LoadAnItemFromArcGISOnline
{
/// <summary>
/// Provides map data to an application
/// </summary>
public class MapViewModel : INotifyPropertyChanged
{
 public MapViewModel()
 {
 InitializeMap();
 }
 private Map _map = new Map(Basemap.CreateTopographic());
 /// <summary>
 /// Gets or sets the map
 /// </summary>
 public Map Map
 {
 get { return _map; }
 set { _map = value; OnPropertyChanged(); }
 }
 /// <summary>
 /// Raises the <see cref="MapViewModel.PropertyChanged" /> event
 /// </summary>
 /// <param name="propertyName">The name of the property that has changed</param>
 protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
 {
 var propertyChangedHandler = PropertyChanged;
 if (propertyChangedHandler != null)
 propertyChangedHandler(this, new PropertyChangedEventArgs(propertyName));
 }
 public event PropertyChangedEventHandler PropertyChanged;
 private async void InitializeMap()
 {
 // Create a portal
 ArcGISPortal portal = await ArcGISPortal.CreateAsync();
 // Hold a portal item ID
 String portalItemId = "883cedb8c9fe4524b64d47666ed234a7";
 // Create the portal item
 PortalItem portalItem = await PortalItem.CreateAsync(portal, portalItemId);
 // Create the layer
 FeatureLayer layer = new FeatureLayer(portalItem, 0);
 // Ensure the layer is loaded
 await layer.LoadAsync();
 // Create the map with updated basemap and initial viewpoint
 this.Map = new Map(Basemap.CreateTopographic()) { InitialViewpoint = new Viewpoint(layer.FullExtent) };
 // Add the layer to the map
 this.Map.OperationalLayers.Add(layer);
 }
}
}

However, I wanted to try using a different layer. The layer I tried it with is a public layer created by the dutch government. It is a layer showing the heights of the netherlands. http://www.arcgis.com/home/webmap/viewer.html?webmap=4feca304f23847feae20eec8fec76fd8

So I simply replaced the ID of the tutorial with the ID from the Dutch layer and it gives me an error with the await layer.LoadAsync();

It sais the following: Esri.ArcGISRuntime.ArcGISRuntimeException: 'Invalid response'

It does show a map with an esri basemap with a global extent. but the app is none responsive.

The entire excercise is done in Visual studio with ArcGIS runtime sdk for .net extension.

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So what I'm thinking is that the dutch layer has a different coordinate system or maybe the layer has a maximum scale, or maybe the issue is that the data is raster. Does anyone has a tip/ know how to fix it, so that I can display this layer and maybe eventually more dutch layers?

Answer 1

Portal items can contain multiple different types of content. Where in the example the item contains a Feature Service (item represents a service endpoint that has trailhead features) and provides metadata to describe the content based on the common portal item metadata model.

enter image description here

The second item contains a webmap. Webmaps (or maps) are items that contain the full map definition including Basemaps and Operational layers. Compared to the item that only contains a single layer, maps can be describe/author the whole map.

enter image description here

So the reason why your code doesn't work is that you try to create a Feature Layer from Map. You can use PortalItemType enum to check which type the item is.

 if (portalItem.Type == PortalItemType.FeatureService)
 {
 // it's a feature service
 // Create the layer
 FeatureLayer layer = new FeatureLayer(portalItem, 0);
 // Ensure the layer is loaded
 await layer.LoadAsync();
 // Create the map with updated basemap and initial viewpoint
 Map = new Map(Basemap.CreateTopographic()) { InitialViewpoint = new Viewpoint(layer.FullExtent) };
 Map.OperationalLayers.Add(layer);
 }
 if (portalItem.Type == PortalItemType.WebMap)
 {
 // Create map from a map definition
 Map = new Map(portalItem);
 }