private ArcGISMapImageSublayer _fileGeodatabaseSublayer;
    private LocalServer _LocalServer;

    public MainWindow()
    {
        InitializeComponent();
        Initialize();
    }
    private async void Initialize()
    {
        // Create a map and add it to the view
        MyMapView.Map = new Map(BasemapType.Topographic, 39.7294, -104.8319, 12);

        try
        {
            // Start the local server instance
            await LocalServer.Instance.StartAsync();
        }
        catch (InvalidOperationException ex)
        {
            MessageBox.Show(String.Format("Please ensure that local server is installed prior to using the sample. See instructions in readme.md or metadata.json. Message: {0}", ex.Message), "Local Server failed to start");
        }
    }
    private void m_Button_Click(object sender, RoutedEventArgs e)
    {
         string filePath = "D:\test\test.gdb";
        string fileName = "featureclass1";
        StartLocalMapService(fileName, filePath);
    }
    private async void StartLocalMapService(string fileName, string filePath)
    {
        // any mpk file -  don't know why
        string mapServiceUrl = System.IO.Path.GetDirectoryName(filePath) + "\mpk_blank.mpk";

        // Create the local map service
        var localMapService = new LocalMapService(mapServiceUrl);
        FileGeodatabaseWorkspace ws = new FileGeodatabaseWorkspace("file_wkspc", filePath);
        TableSublayerSource source = new TableSublayerSource(ws.Id, fileName);
        _fileGeodatabaseSublayer = new ArcGISMapImageSublayer(0, source);
        localMapService.SetDynamicWorkspaces(new List<DynamicWorkspace>()
        {
            ws
        });
        localMapService.StatusChanged += localMapService_StatusChanged;
        await localMapService.StartAsync();
    }
    private async void localMapService_StatusChanged(object sender, StatusChangedEventArgs e)
    {
        if (e.Status == LocalServerStatus.Started)
        {
            if (!(sender is LocalMapService localService))
            {
                return;
            }
            ArcGISMapImageLayer imageryLayer = new ArcGISMapImageLayer(localService.Url);
            imageryLayer.LoadStatusChanged += (q, ex) =>
            {
                // Add the layer to the map once loaded
                if (ex.Status == Esri.ArcGISRuntime.LoadStatus.Loaded)
                {
                    // Create a default symbol style
                    SimpleLineSymbol lineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, System.Drawing.Color.Red, 3);
                    // Apply the symbol style with a renderer
                    _fileGeodatabaseSublayer.Renderer = new SimpleRenderer(lineSymbol);
                    imageryLayer.Sublayers.Add(_fileGeodatabaseSublayer);
                }
            };
            await imageryLayer.LoadAsync();
            MyMapView.Map.OperationalLayers.Clear();
           // Add the image layer to the map
            MyMapView.Map.OperationalLayers.Add(imageryLayer);
        }
    }