BornToBeRoot/NETworkManager · error · FileNotFoundException

Embedded resource…

Error message

Embedded resource "NETworkManager.Resources.Maps.world-cities.json" not found.

What it means

TracerouteMapControl loads city coordinates from the embedded resource "NETworkManager.Resources.Maps.world-cities.json" via GetManifestResourceStream. When that resource is not present in the executing assembly, the null stream triggers a FileNotFoundException with this message, so the traceroute map cannot plot city locations.

Solutions

Ensure the csproj embeds the file (<EmbeddedResource Include="Resources\Maps\world-cities.json" />) and rebuild.
Check the exact resource name (default namespace + folder path) matches the constant; fix either the path or the resourceName.
Debug with assembly.GetManifestResourceNames() to see which names actually exist and align them.
Restore the missing world-cities.json from the repository and rebuild/redeploy the complete output.

Example fix

// csproj before
<None Remove="Resources\Maps\world-cities.json" />
// after
<EmbeddedResource Include="Resources\Maps\world-cities.json" />

Defensive patterns

Strategy: fallback

Validate before calling

var names = Assembly.GetExecutingAssembly().GetManifestResourceNames();
bool ok = names.Contains("NETworkManager.Resources.Maps.world-cities.json");

Try / catch

try
{
    var cities = LoadCities();
}
catch (FileNotFoundException ex)
{
    logger.Error("world-cities.json embedded resource missing", ex);
    MessageBox.Show("City data is missing from this installation. Please reinstall.");
}

Prevention

Ensure the csproj marks world-cities.json as EmbeddedResource.
Add a CI smoke test that enumerates manifest resources and checks both map JSON files.
Keep resource folder structure aligned with the default namespace so names stay stable.
Deploy full build outputs; verify resources after any packaging changes.

When it happens

Trigger: The resource loader is invoked (TracerouteMapControl construction) while the assembly lacks a manifest resource named exactly "NETworkManager.Resources.Maps.world-cities.json" — missing EmbeddedResource entry in the csproj, renamed/moved file, or a build that excluded the Resources/Maps folder.

Common situations: Custom or CI builds that did not embed the JSON; the file moved to another folder so the default-namespace-derived resource name changed; resource-stripping publish profiles; a locally modified repo missing the data file.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

AI-assisted analysis of BornToBeRoot/NETworkManager@2780d65469 (2026-09-12). Data as JSON: /api/errors/de80e65fb4885b33. Report an issue: GitHub.

Appendix: source

Thrown at Source/NETworkManager/Controls/TracerouteMapControl.xaml.cs:1681

    /// Minimal representation of a simplified country outline (name + outer ring coordinates as [lon, lat] pairs).
    /// </summary>
    private sealed class CountryData
    {
        [JsonPropertyName("n")]
        public string N { get; set; }

        [JsonPropertyName("r")]
        public List<List<List<double>>> R { get; set; }
    }

    private static List<CityData> LoadCities()
    {
        const string resourceName = "NETworkManager.Resources.Maps.world-cities.json";

        var assembly = Assembly.GetExecutingAssembly();

        using var stream = assembly.GetManifestResourceStream(resourceName) ??
                            throw new FileNotFoundException($"Embedded resource \"{resourceName}\" not found.");
        using var reader = new StreamReader(stream);

        return System.Text.Json.JsonSerializer.Deserialize<List<CityData>>(reader.ReadToEnd()) ?? [];
    }

    /// <summary>
    /// Minimal representation of a major city (national capital or population above the script's threshold).
    /// </summary>
    private sealed class CityData
    {
        [JsonPropertyName("n")]
        public string N { get; set; }

        [JsonPropertyName("lat")]
        public double Lat { get; set; }

        [JsonPropertyName("lon")]
        public double Lon { get; set; }

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