The Silverlight Bing Maps Control library has a MapPolygon control to allow you to overlay geo-located polygons over your Bing Map.
Public Class MapPolygonExtended
Inherits Microsoft.Maps.MapControl.MapPolygon
Public Shared ReadOnly FillProperty As DependencyProperty = DependencyProperty.RegisterAttached("Fill", GetType(Brush), GetType(MapPolygonExtended),
New PropertyMetadata(New PropertyChangedCallback(AddressOf FillChangedCallback)))
Public Overloads Property Fill() As Brush
Get
Return MyBase.Fill
End Get
Set(ByVal value As Brush)
MyBase.Fill = value
End Set
End Property
Private Shared Sub FillChangedCallback(ByVal d As DependencyObject, ByVal e As DependencyPropertyChangedEventArgs)
Dim dlb As MapPolygonExtended = CType(d, MapPolygonExtended)
dlb.Fill = CType(e.NewValue, Brush)
End Sub
End Class
If it is another type such as a Color or String then you will need to use a binding converter.
I hope this can help people setup bound MapPolygon.