The new release of Silverlight 3.0 RTW comes with an implementation of this component that fill this hole but it has the same limitations of my CollectionViewSource. This limitations come from the same reason I cannot implement by myself: the missing grouping support in ItemsControls. However the native component has a some advantages on mine, first of all a very strict compatibility with the architecture of the WPF CollectionViewSource. In this post I will show you how to configure and use the component in a Silverlight application.

[http://silverlightplayground.boschin.it/post/2009/07/10/Silverlight-30-RTW-The-CollectionViewSource.aspx]