C# Multiple Order By with LINQ

               

먼저 Orderby( e=> e.Field<string>("A1")). ThenBy(e => e.Field("A2")) 또는 ThenByDescending(e => e.Field<string>("A2"))

 

 DataTable query2 = new DataTable();
                 query2 =Result_DTL.AsEnumerable()
                            .GroupBy(row => new
                            {
                                TEC1 = row.Field<string>("a1"),
                                Grade1 = row.Field<string>("a2")
                            })
                            .Select(gcs =>
                            {
                                var row = Result_DTL.NewRow();
                                row["a1"] = gcs.Key.TEC1;
                                row["a2"] = gcs.Key.Grade1;
                                return row;
                            })
                            .OrderBy(e => e.Field<string>("a1")).ThenByDescending(e => e.Field<string>("a2"))
                            .CopyToDataTable();