Visifire have some nice open source chart controls for Silverlight:
All I wanted it to do was put the control on an UpdatePanel, and refresh its datasource on a Client CallBack.
Luckially one guy called Reyza ( and according to google only one) has worked this out in Indonesian:
( What are the chances? I actually just went to Jakarta 🙂 )
Add the following code DIRECTLY after your UpdatePanel like this:
Basically it just builds it again after an update.