Use
DataView.ToTable[
^]:
DataTable dt = (some query expression);
dt.DefaultView.RowFilter = " ... ";
DataTable dt2 = dt.DefaultView.ToTable();
Note that this will copy the data. But I think that that has to happen for any solution to your problem, because you want to leave the initial table intact and not use a combined filter expression (which would be how you would create a double-filtered view without copying data).