Gerard,

I don't know if the mapping name property will allow an expression (I've never tried it). But you could add a column to your datatable that's based on an expression, like so:

DataColumn MyCol = new DataColumn("NewString", typeof(System.String));
MyCol.Expression = "Col1 + Col2 + Col3";
MyTable.Columns.Add(MyCol);

I'm actually curious now to see if there are other ways, but I believe at least that one should work.

Kevin