Silverlight 3 Datagrid. How to access to the current sort properties

I'm using a DataGrid, which datasource is exported to Excel.

I'd like to shape the excel doc according to the current sorting of the DataGrid (which column, and which order).

Anyone knows how to access this information?

Thanks

solution: Use a PagedCollectionView as a wrapper for your datasource.

If a sort is used, there will be an item in the SortDescriptions property of the PagedCollectionView, that will give access to the PropertyName on which the grid is sorted, and on the sort direction.