public event LayerItemsGeneratingEventHandler LayerItemsGenerating

Public Event LayerItemsGenerating As LayerItemsGeneratingEventHandler

<dxm:InformationLayer EnableHighlighting="False">
    <dxm:InformationLayer.DataProvider>
        <dxm:BingRouteDataProvider x:Name="routeProvider" 
                                   BingKey="{Binding Source={StaticResource YourBingKey}}"
                                   LayerItemsGenerating="routeProvider_LayerItemsGenerating"/>
    </dxm:InformationLayer.DataProvider>
</dxm:InformationLayer>

public partial class MainWindow : Window {

    public MainWindow() {
        InitializeComponent();

        // Create three waypoints and add them to a route waypoints list. 
        List<RouteWaypoint> waypoints = new List<RouteWaypoint>();
        waypoints.Add(new RouteWaypoint("New York", new GeoPoint(41.145556, -73.995)));
        waypoints.Add(new RouteWaypoint("Oklahoma", new GeoPoint(36.131389, -95.937222)));
        waypoints.Add(new RouteWaypoint("Las Vegas", new GeoPoint(36.175, -115.136389)));

        routeProvider.CalculateRoute(waypoints);
    }

    private void routeProvider_LayerItemsGenerating(object sender, LayerItemsGeneratingEventArgs args) {
        char letter = 'A';
        foreach (MapItem item in args.Items) {
            MapPushpin pushpin = item as MapPushpin;
            if (pushpin != null)
                pushpin.Text = letter++.ToString();
            MapPolyline line = item as MapPolyline;
            if (line != null) {
                line.Fill = Brushes.Red;
                line.Stroke = Brushes.Red;
            }
        }

        map.ZoomToFit(args.Items);
    }
}

Public Sub New()
            InitializeComponent()

            ' Create three waypoints and add them to a route waypoints list. 
            Dim waypoints As New List(Of RouteWaypoint)()
            waypoints.Add(New RouteWaypoint("New York", New GeoPoint(41.145556, -73.995)))
            waypoints.Add(New RouteWaypoint("Oklahoma", New GeoPoint(36.131389, -95.937222)))
            waypoints.Add(New RouteWaypoint("Las Vegas", New GeoPoint(36.175, -115.136389)))

            routeProvider.CalculateRoute(waypoints)
        End Sub

        Private Sub routeProvider_LayerItemsGenerating(ByVal sender As Object, ByVal args As LayerItemsGeneratingEventArgs)
            Dim letter As Char = "A"c

            For Each item As MapItem In args.Items
                Dim pushpin As MapPushpin = TryCast(item, MapPushpin)
                If pushpin IsNot Nothing Then
                    pushpin.Text = letter.ToString()
                    letter = ChrW(AscW(letter) + 1)
                End If
                Dim line As MapPolyline = TryCast(item, MapPolyline)
                If line IsNot Nothing Then
                    line.Fill = System.Windows.Media.Brushes.Red
                    line.Stroke = System.Windows.Media.Brushes.Red
                End If
            Next item
            map.ZoomToFit(args.Items)
        End Sub

SearchCompleted="OnSearchCompleted"
                            LayerItemsGenerating="OnLayerItemsGenerating" />
<!--endregion #SearchCompleted-->

#line 33 "..\..\..\MainWindow.xaml"
this.searchDataProvider.LayerItemsGenerating += new DevExpress.Xpf.Map.LayerItemsGeneratingEventHandler(this.OnLayerItemsGenerating);

#ExternalSource("..\..\..\MainWindow.xaml",33)
AddHandler Me.searchDataProvider.LayerItemsGenerating, New DevExpress.Xpf.Map.LayerItemsGeneratingEventHandler(AddressOf Me.OnLayerItemsGenerating)