I cannot be sure about your implementation, this is why I will try to explain how your requirement can be achieved based on our Map Shapes Virtualization article
. If you take a look at the sample implementation of the MapItemsRequest() method inside ShapeVirtualization class, you will see how a reference to the Layer is saved. Please note that the DataContext of your MainWindow should propagate to the RadMap and also to the VisualizationLayer.
Please give this approach a try and let us now if you need any further assistance.
Pavel R. Pavlov
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