Support for Arbitrary Dictionary Keys
In XAML 2006 all explicit x:Key value were threatedtreated as strings. In XAML 2009 you can define any type of key you like by writing the key in ElementSyntax.
<!-- XAML 2006 --> <StreamGeometry x:Key="CheckGeometry">M 0 0 L 12 8 l 9 12 z</StreamGeometry> <!-- XAML 2009 --> <StreamGeometry>M 0 0 L 12 8 l 9 12 z <x:Key><x:Double>10.0</x:Double></x:Key> </StreamGeometry>