Vanessa,
The simplest way is to add a column to the DataTable and set its expression
property to be Max(colname) where colname is the field you are interested
in. Every row in the datatable will then have a field with the same value.
Alternatively, you can create a second datatable with a relationship to the
first, and add the expression column to the second table. Then the
aggregation (Max) will be carried out on a grouping basis via the
relationship.
You can also use a DataView, set it to sort by the field in question, then
retrieve the first row from the sorted dataview.
Hope this helps,
Neil.