LINQ

var query = from row in dt.AsEnumerable()
     where row.Field<string>("MinValue") != null && row.Field<string>("MaxValue") != null
     group row by row.Field<string>("Name") into grp
     let maxServiceDate = grp.Max(r => r.Field<DateTime>("ServiceData")) 
 
     from row in grp
     where row.Field<string;>("ServiceData") == maxServiceDate 
     select row