1. Manually update the text shown in the application by listening for the ExtentChanged property of the map.2. Write a value converter, to bind the Map.Extent to, but pass the map's instance as a converter parameter to the class and return the scale as the value.3. Wrap the map. For example:<TextBlock x:Name="ScaleText" Text="{ Binding ElementName=MyMap, Path=Extent, Converter={StaticResource SC}, ConverterParameter={x:Reference Name=MyMap}}" FontSize="12" FontWeight="Bold" Foreground="Black"/>public class SC : IValueConverter{public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture){double scale = 0.0;if (parameter is Map) scale = ((Map)parameter).Scale;return scale;}public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture){return value;}}