UtilityNetworkTraceTool Doesn't Load when Adding Utility Network As Layer, Not via Webmap

[AmrEldib]

We have a client who's working with the UtilityNetworkTraceTool control. The control supports loading networks and named trace configurations from a web map.
However, when trying to add the utility network as a layer, the control doesn't fully load.

Does the control support this approach? What methods/properties need to be called/set to make this happen?
Or, is there a bug in this behavior?

The control is initially not loaded.

Then, the user clicks "Add data" to load the layer, which is loaded (as well as the utility network).
The control reacts (a loading symbol briefly appears, then the control is back).

However, the user needs to switch tabs to see that the control has loaded.
Then, you can see that no Trace Types were loaded.

Here's the code (XAML file renamed to txt to allow uploading).
Use the dotnet-samples. Under src\MAUI\Maui.Samples\Samples, you can add a new folder (named "UtilityNetworkTrace" for example), then place the files there.

UtilityNetworkTraceToolSample.xaml.txt

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage
    x:Class="Toolkit.SampleApp.Maui.Samples.UtilityNetworkTraceToolSample"
    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:esriTK="clr-namespace:Esri.ArcGISRuntime.Toolkit.Maui;assembly=Esri.ArcGISRuntime.Toolkit.Maui"
    xmlns:esriUI="clr-namespace:Esri.ArcGISRuntime.Maui;assembly=Esri.ArcGISRuntime.Maui"
    Title="UtilityNetworkTraceTool">
    <ContentPage.Resources>
        <Style TargetType="Grid">
            <Setter Property="Background" Value="{AppThemeBinding Dark=#353535, Light=#F8F8F8}" />
        </Style>
    </ContentPage.Resources>


    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition />
            <ColumnDefinition  />
        </Grid.ColumnDefinitions>
        <Grid Grid.Column="0">
            <Grid.RowDefinitions>
                <RowDefinition Height="*"/>
                <RowDefinition Height="Auto"/>
            </Grid.RowDefinitions>
            <esriUI:MapView Grid.Row="0"  x:Name="MyMapView" />
            <Button Grid.Row="1"  x:Name="LoadDataButton" Text="Load Data" Clicked="LoadDataButton_Clicked"  Margin="10"/>
        </Grid>
        <VerticalStackLayout Grid.Column="1">
            <esriTK:UtilityNetworkTraceTool GeoView="{Binding Source={x:Reference MyMapView}}" x:Name="MyTraceTool"/>
        </VerticalStackLayout>
    </Grid>
</ContentPage>

UtilityNetworkTraceToolSample.xaml.cs

using Esri.ArcGISRuntime;
using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Security;
using Esri.ArcGISRuntime.UtilityNetworks;
using Microsoft.Maui.ApplicationModel;
using System.Diagnostics;

namespace Toolkit.SampleApp.Maui.Samples
{
    [XamlCompilation(XamlCompilationOptions.Compile)]
    [ArcGIS.Samples.Shared.Attributes.Sample(name: "UtilityNetworkTraceTool Issue", category: "UtilityNetworkTraceTool Issue", description: "Use named trace configurations defined in a web map to perform connected trace operations and compare results.", instructions: "Tap on one or more features while 'Add starting locations' or 'Add barriers' is selected. When a junction feature is identified, you may be prompted to select a terminal. When an edge feature is identified, the distance from the tapped location to the beginning of the edge feature will be computed. Select the type of trace using the drop down menu. Tap 'Trace' to initiate a trace on the network. Tap 'Reset' to clear the trace parameters and start over.",
        tags: new[] { "condition barriers", "downstream trace", "network analysis", "subnetwork trace", "toolkit", "trace configuration", "traversability", "upstream trace", "utility network", "validate consistency" })]
    public partial class UtilityNetworkTraceToolSample : ContentPage
    {
        private const string WebmapURL = "https://www.arcgis.com/home/item.html?id=471eb0bf37074b1fbb972b1da70fb310";

        public UtilityNetworkTraceToolSample()
        {
            InitializeComponent();

            MyTraceTool.UtilityNetworkChanged += MyTraceTool_UtilityNetworkChanged;
            MyTraceTool.UtilityNetworkTraceCompleted += MyTraceTool_UtilityNetworkTraceCompleted;
            AuthenticationManager.Current.ChallengeHandler = new ChallengeHandler(Challenge);
            Initialize();
        }

        private void MyTraceTool_UtilityNetworkTraceCompleted(object? sender, Esri.ArcGISRuntime.Toolkit.Maui.UtilityNetworkTraceCompletedEventArgs e)
        {
            System.Diagnostics.Debug.WriteLine($"Trace completed {e}");
        }

        private void MyTraceTool_UtilityNetworkChanged(object? sender, Esri.ArcGISRuntime.Toolkit.Maui.UtilityNetworkChangedEventArgs e)
        {
            System.Diagnostics.Debug.WriteLine($"Network changed. New selection: {e.UtilityNetwork?.Name}");
        }

        private async void Initialize()
        {
            try
            {

                var basemapLayer = new ArcGISVectorTiledLayer(new Uri("https://www.arcgis.com/home/item.html?id=86f556a2d1fd468181855a35e344567f"));
                await basemapLayer.LoadAsync();
                var map = new Esri.ArcGISRuntime.Mapping.Map(SpatialReferences.WebMercator) { Basemap = new Basemap(basemapLayer) };
                //var map = new Esri.ArcGISRuntime.Mapping.Map(new Uri(WebmapURL));

                MyMapView.Map = map;
                //MyTraceTool.GeoView = MyMapView;         
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine(ex);
            }
        }


        public async Task<Credential> Challenge(CredentialRequestInfo info)
        {
            try
            {
                // WARNING: Never hardcode login information in a production application. This is done solely for the sake of the sample.
                string sampleServer7User = "viewer01";
                string sampleServer7Pass = "I68VGU^nMurF";

                return await AccessTokenCredential.CreateAsync(info.ServiceUri, sampleServer7User, sampleServer7Pass);
            }
            catch (Exception ex)
            {
                return null;
            }
        }

        private async void LoadDataButton_Clicked(object sender, EventArgs e)
        {
            MyMapView.Map.OperationalLayers.Clear();
            var parentUrl = "https://sampleserver7.arcgisonline.com/server/rest/services/UtilityNetwork/NapervilleElectricV5/FeatureServer";
            var parentUri = new Uri(parentUrl);
            
            var serviceGeodatabase = new ServiceGeodatabase(parentUri);

            await serviceGeodatabase.LoadAsync();
            if (serviceGeodatabase.LoadStatus != LoadStatus.Loaded)
            {
                Debug.WriteLine("serviceGeodatabase didn't load");
                return;
            }
            try
            {

                // Add the UN to the map BEFORE loading it — the map must own it
                // and only unloaded UtilityNetworks can be added to Map.UtilityNetworks
                var un = new UtilityNetwork(serviceGeodatabase);
                
                //MainThread.BeginInvokeOnMainThread(() => MyMapView.Map.UtilityNetworks.Add(un));
                MyMapView.Map.UtilityNetworks.Add(un);

                //FOR SOME REASON ALL THE LAYERS FROM THE SERVICEGEODATABASE WONT LOAD ON THE MAP
                foreach (var layerInfo in serviceGeodatabase.ServiceInfo.LayerInfos)
                {
                    try
                    {
                        var serviceFeatureTable = serviceGeodatabase.GetTable((long)layerInfo.Id);
                        if (serviceFeatureTable == null) continue;

                        if (serviceFeatureTable.LoadStatus != LoadStatus.Loaded)
                            await serviceFeatureTable.LoadAsync();
                        if (serviceFeatureTable.LayerInfo == null) continue;

                        var subTypeFeatureLayer = new SubtypeFeatureLayer(serviceFeatureTable);
                        if (subTypeFeatureLayer.LoadStatus != LoadStatus.Loaded)
                            await subTypeFeatureLayer.LoadAsync();

                        //MainThread.BeginInvokeOnMainThread(() => MyMapView.Map.OperationalLayers.Add(subTypeFeatureLayer));
                        MyMapView.Map.OperationalLayers.Add(subTypeFeatureLayer);
                    }
                    catch
                    {
                        continue;
                    }
                }
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine($"Error: {ex}");
            }
            finally
            {
                //MyTraceTool.GeoView = MyMapView;
                
            }
        }
    }
}

[jnery]

Hi, thank you for your feedback.

UtilityNetworkTraceTool is meant to work with web/mobile maps with named traces shared; so, an empty list in your scenario is expected as designed.

Here's how you would configure the map with named traces in ArcGISPro or in MapViewer (screenshots below).

MapViewer > Gear icon > Configure traces	Select one or many

Internally, the toolkit calls GetNamedTraceConfigurationsFromUtilityNetworkAsync. However, you may be expecting QueryNamedTraceConfigurationsAsync.

Notice, there's a difference between these two results using your scenario. The former would be empty since no trace has been shared with the map and all traces available in the utility network for the latter.

var namedTracesForMap = await map.GetNamedTraceConfigurationsFromUtilityNetworkAsync(utilityNetwork);
var allNamedTraces = await utilityNetwork.QueryNamedTraceConfigurationsAsync(null);

As to why you're not seeing features in the map - In order to honor the map's spatial reference, you need to add the layer before loading the table; otherwise, the table's spatial reference is used.

Note also that you need to add the utility network to the map prior to loading it or Map.UtilityNetworks.Add() would fail.

Consider the following code instead for loading the layers.

var map = new Map(BasemapStyle.ArcGISStreets);

var serviceGeodatabase = new ServiceGeodatabase(new Uri(FeatureServiceURL));
var utilityNetwork = new UtilityNetwork(serviceGeodatabase);
map.UtilityNetworks.Add(utilityNetwork);

MyMapView.Map = map;

await map.LoadAsync();
await utilityNetwork.LoadAsync();
await serviceGeodatabase.LoadAsync();

ArgumentNullException.ThrowIfNull(serviceGeodatabase.ServiceInfo);
foreach (var idInfo in serviceGeodatabase.ServiceInfo.LayerInfos)
{
    map.OperationalLayers.Insert(0, new SubtypeFeatureLayer(serviceGeodatabase.GetTable(idInfo.Id)));
}

[AmrEldib]

Thanks for your reply, @jnery
I've discussed the points you've mentioned with the client. As you pointed out, the result is different when using GetNamedTraceConfigurationsFromUtilityNetworkAsync compared to using QueryNamedTraceConfigurationsAsync.
The question is: why is that the case?
You explained that no traces has been shared with the map, but it's not clear how to share these traces with the map at the moment of loading the utility network and add it to the map (instead of creating a webmap).

For the client, they have a use case where layers and utility networks are added at runtime by the application user. Using webmaps is not an option for them.

Is this workflow not supported by the control, or is there a way to programmatically load these trace configurations into the control?

Right now, the client needs to download the source code of the toolkit, modify a single line of code (see screenshot) and include it in their project to workaround this issue.

[jnery]

The question is: why is that the case?
You explained that no traces has been shared with the map, but it's not clear how to share these traces with the map at the moment of loading the utility network and add it to the map (instead of creating a webmap).

For a map constructed outside portal or offline map workflow, there is no way to configure the map with a filtered list of named traces.

Yes, this is place where you can override which method to call to change its intended behavior.

[AmrEldib]

Thanks for the clarification @jnery
Can this be turned into an enhancement request; to add the ability to configure the map with a filtered list of named traces without relying on a webmap.

This is an essential workflow for our client. They have a use case where layers and utility networks are added at runtime by the application user. Using webmaps is not an option for them.