I was chatting with a customer last week about how they were using Silverlight for their B2B portal.  They were having some difficulty with showing and hiding the DataGrid component’s Row Detail template programmatically.  I found a WPF-oriented solution to the problem on StackOverflow and adapted it to an Expression Blend Behavior to make the solution more modular and reusable.

I posted the behavior with a sample to the Expression Gallery.  If you try it out, please give it an appropriate rating.