Free Excel spreadsheet Component for SilverLight?

I Need a Good Excel spreadsheet Component for Silver Light. I mean F开发者_开发知识库ree ones!!!

DataGrid is quiet good. Though you might end up writing a few lines of code here and there to implement a few extra features so that it matches the functionality of Excel (you know, things like filtering, sorting, automatic value recalculation, persistence, printing, etc.) but it is a Free one!!!