InformationDataProviderBase.LayerItemsGenerating Event

Occurs when a data provider starts generating map items for a layer.

Namespace: DevExpress.Xpf.Map

Assembly: DevExpress.Xpf.Map.v21.1.dll


public event LayerItemsGeneratingEventHandler LayerItemsGenerating

Event Data

The LayerItemsGenerating event's data class is LayerItemsGeneratingEventArgs. The following properties provide information specific to this event:

Property Description
Cancelled Gets a value indicating whether an asynchronous operation has been canceled. Inherited from AsyncCompletedEventArgs.
Error Gets a value indicating which error occurred during an asynchronous operation. Inherited from AsyncCompletedEventArgs.
Items Returns all the items generated for the layer.
UserState Gets the unique identifier for the asynchronous task. Inherited from AsyncCompletedEventArgs.

The event data class exposes the following methods:

Method Description
RaiseExceptionIfNecessary() Raises a user-supplied exception if an asynchronous operation failed. Inherited from AsyncCompletedEventArgs.


This example demonstrates how to calculate a route between several waypoints and change the appearance of a route path using the Microsoft Bing Route web service. To accomplish this, do the following.


If you run the application, and see a window with the following error message: ”The specified Bing Maps key is invalid. To create a developer account, refer to”, refer to the following tutorial: How to: Get a Bing Maps Key.

View Example

Public Sub New()

    ' 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)))

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
See Also