InformationLayer.ClearResults() Method

Clears all results displayed on a layer.

Namespace: DevExpress.Xpf.Map

Assembly: DevExpress.Xpf.Map.v24.1.dll

NuGet Package: DevExpress.Wpf.Map

Declaration

C#

public void ClearResults()

VB.NET

Public Sub ClearResults

Example

This example demonstrates how to use the Microsoft Bing Route web service to calculate a route between multiple waypoints and how to customize the appearance of the resulting route path.

Important

On May 21, 2024, Microsoft announced that Bing Maps for Enterprise and its API will be discontinued. Azure Maps will be a single unified enterprise mapping platform available from Microsoft.

We are working on API compatible with Azure Maps and expect to ship it with our next major release (v24.2).

If you have an existing license to Bing Maps for Enterprise, you can continue using our existing API. You need to transition to new API until June 30, 2025 (free and basic license) or until June 30, 2028 (enterprise license).

The last date you can get a new license to Bing Maps for Enterprise is June 30, 2025. If you do not have an existing license after that date, you would not be able to use our map controls with Bing Maps or Azure Maps (until we release the new API). During that time, you can use other map providers supported by our controls, such as OpenStreetMap.

To accomplish this, do the following:

• Create an InformationLayer object and add it to the MapControl.Layers collection.

• Create a BingRouteDataProvider object and assign it to the InformationLayer.DataProvider property. Specify the provider’s key. For more information, refer to the following help topic: How to: Get a Bing Maps Key.

• To calculate a route, call the BingRouteDataProvider.CalculateRoute method and pass a list of waypoints as its argument.

  Note

  The BingRouteDataProvider.CalculateRoute method calculates the route based on less than 265 RouteWaypoint objects.

• To customize the resulting route path’s appearance, handle the InformationDataProviderBase.LayerItemsGenerating event and configure appearance of the items contained in the event arguments (the Itemsproperty). This example shows how to specify text displayed in generated pushpins and define colors used to draw the path between pushpins.

  The Map Control generates map pushpins for waypoints and raises the LayerItemsGenerating event only when the InformationDataProviderBase.GenerateLayerItems property value is true. If the GenerateLayerItems property value is false, you can create pushpins or other map vector items based on your waypoints in the BingRouteDataProvider.RouteCalculated event handler.

MainWindow.xaml

<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>

MainWindow.xaml.cs

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);
    }
}

MainWindow.xaml.vb

        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