MapPushpin.TraceDepth Property

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
    Next item
End Sub

<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 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();
    }
}