Find sort order in DataGrid

I am simply trying to get the sort order of the column clicked in a datagrid (ASC, DESC) so that I can add it to my SQL statement on the next query. Does anyone know how to access this property?

Using a mousedown or mouseup event, I can get the column that was last clicked which provides the "sort by Columnname" part, but I need the asc or desc part as well.

Thanks,
Bebandit