linq查询联接表的多个orderby

我有以下LINQ查询

   var CGTABLE = (from cg in DbContext.CGTABLE
                              join tcg in DbContext.TCGTABLE on new { cg.CGroupId } equals new { tcg.CGroupId }                                                                    
                              where tcg.TId == TId
                              select new  {
                                  CGroupId = cg.CGroupId,
                                  CGroupCode = cg.CGroupCode,                                      
                                  Description = cg.Description,                                      
                                  C = cg.C,
                                  DisplayOrder = cg.DisplayOrder
                              }).ToList();

        CGTABLE = CGTABLE.OrderBy(g => g.DisplayOrder).ThenBy(g => g.C.OrderBy(c => c.CCode)).ToList();

运行良好,但使用Thenby不会执行第二个顺序 ThenBy(g => g.C.OrderBy(c => c.CCode) 我错过了什么?

Sample data for better understanding.
Data in Tables
2
  1
  2
  4
  3
1
  4
  5
  2
  1
3
  3
  1

Should output after both outer and inner list ordered by
1
  1
  2
  3
  4
2
  1
  2
  4
  5
3
  1
  3

But Currently it is showing
1
  4
  5
  2
  1
2
  1
  2
  4
  3
3
  3
  1