Like this http://forums.silverlight.net/forums/p/62122/460886.aspx
+1
A:
I'm not sure which background you are trying to change, but you can set any background by overriding the ComboBox
's ControlTemplate. Your best bet is probably to copy the default ComboBox
ControlTemplate from here and then modify the necessary background to match your needs.
Stephan
2010-10-15 17:48:57