同时使用两个字段排列
SfaMember.GetList(searchInfo, 0, 1000, out Allcount).Where(item => item.bOpen == true).OrderBy(item => item.Department).ThenBy(item=>item.SubId).GroupBy(item => item.Department);
注:第一个字段用OrderBy,第二个字段用ThenBy(正序)
倒序用OrderByDescending和ThenByDescending