C# 更新集合中某一个信息也是集合的数据

比如一个集合中，还有一个多选项，此多选项是作为一个集合，传输在总的集合上，更新这个多选项集合的代码

1.先更新总集合的基本数据

2.针对这个多选项集合的值，更新多选项

 1 //从DB删除已经删除的问题
 2                     if (exam.ID > 0)
 3                     {
 4                         var sql = string.Empty;
 5                         if (exam.Questions.Where(o => o.ID > 0).Count() > 0)
 6                         {
 7                             sql = string.Format("UPDATE dbo.Question SET IsDeleted = 1 WHERE IsDeleted = 0 AND ExamSn = '{0}' AND ID NOT IN ({1})", exam.Sn, string.Join(",", exam.Questions.Where(o => o.ID > 0).Select(o => o.ID)));
 8                         }
 9                         else
10                         {
11                             sql = string.Format("UPDATE dbo.Question SET IsDeleted = 1 WHERE IsDeleted = 0 AND ExamSn = '{0}'", exam.Sn);
12                         }
13                         db.ExecuteNonQuerySql(sql);
14                     }
15                     foreach (var q in exam.Questions)
16                     {
17                         var q_result = false;
18                         if (q.ID == 0)
19                         {
20                             q.IsDeleted = false;
21                             q.Sn = Guid.NewGuid();
22                             q.ExamSn = exam.Sn;
23                             q_result = service.Create(q);
24                         }
25                         else
26                         {
27                             q_result = service.Update(q);
28                         }30                     }