Linq 查询中的有线代理运算符

Question

这是我的查询：

db.Users.Where(u =>
  ( u.Mobile.Contains(SearchStr)
   || u.FirstName.ToLower().Contains(SearchStr.ToLower())
   || u.LastName.ToLower().Contains(SearchStr.ToLower())
   || (u.Email.Contains(SearchStr)
  )
  && (u.Type == SearchType || SearchType == 0)
  && (Confirmed == null || Confirmed == u.IsVerified)
  && (Banned == null || Banned == u.IsDeleted)
 )

此列表忽略 Confirmed、Banned 和 SearchType 的所有用户。无论这些值是 null、true 还是 false

，结果都是相同的

Answer 1

If SearchType == 0 or Confirmed == null or Banned == null 在任何时候，它都会 return 一切。很有可能是这样

除去那些条件，你应该很好

Answer 2

这里更多的是评论然后回答，但想显示可能有助于 OP 调试的代码

  db.Users.Where(u =>ISPassed(u));

    private bool IsPassed(User u)
    {
// put a debugger here
     return ( u.Mobile.Contains(SearchStr)
       || u.FirstName.ToLower().Contains(SearchStr.ToLower())
       || u.LastName.ToLower().Contains(SearchStr.ToLower())
       || (u.Email.Contains(SearchStr)
      )
      && (u.Type == SearchType || SearchType == 0)
      && (Confirmed == null || Confirmed == u.IsVerified)
      && (Banned == null || Banned == u.IsDeleted));
    }

Answer 3

我认为问题出在此处的左括号

(u.Email.Contains(SearchStr)

这基本上使条件类似于 A OR B OR C AND D AND E AND F。我不知道（我什至不想知道）这样的逻辑表达式是如何计算的，很可能结果不是你所期望的。

试试这个

var query = db.Users.Where(u =>
    (u.Mobile.Contains(SearchStr)
       || u.FirstName.ToLower().Contains(SearchStr.ToLower())
       || u.LastName.ToLower().Contains(SearchStr.ToLower())
       || u.Email.Contains(SearchStr)
    )
    && (u.Type == SearchType || SearchType == 0)
    && (Confirmed == null || Confirmed == u.IsVerified)
    && (Banned == null || Banned == u.IsDeleted)
);

Answer 4

我看生成的sql如Ivan Stoev所说。添加另一对括号解决了问题，但我仍然不明白逻辑，为什么以前没有工作，为什么现在工作

db.Users.Where(
                        u =>
                        ((  u.Mobile.Contains(SearchStr) //added the parantheses in here
                        || u.FirstName.ToLower().Contains(SearchStr.ToLower())
                        || u.LastName.ToLower().Contains(SearchStr.ToLower())
                        || (u.Email.Contains(SearchStr)
                        )) //and here
                        && (u.Type == SearchType || SearchType == 0)
                        && (Confirmed == null || Confirmed == u.IsVerified)
                        && (Banned == null || Banned == u.IsDeleted)

                        ))

Linq 查询中的有线代理运算符

wired acting operators in Linq query

c#

linq

linq-to-entities