Linq如何返回匿名类型的IQueryable以获得其记录数？

Question

The following Linq query returns an IQueryable of anonymous type:

var users2 = from u1 in Users
         join u2 in distribs on u1.pDistribId equals u2.Id
         into temp
         from u3 in temp.DefaultIfEmpty()
         select new {
             u1.Id,
             u1.UserName,
             u1.pDistribId,
             pUserName = u3 == null ? "" : u3.UserName,
             u1.Phone,
             u1.Name,
             u1.pCustomUser,
             u1.CoName,
             u1.CoPhone,
             u1.Birthday,
             u1.QQ,
             u1.Email,
             u1.SelfIntr
         };

To get the number of records for users2, use the following method:

var c = users2.Count();

Error in result:

Dbcomparonexpression requires parameters of a comparable type.

How does an IQueryable type like this anonymous type get its record count?

Complete source code：

users：

var Users = from u in UserManager.Users
                        where u.Equals("user")
                        select new { u.Id, u.UserName, u.pDistribId, u.Phone, u.Name, u.CoName, u.CoPhone, u.pCustomUser, u.Birthday, u.QQ, u.Email, u.SelfIntr };

distribs：

var distribs = from u in UserManager.Users
                           where u.Role.Equals("distrib")
                           select new { u.Id, u.UserName, u.pDistribId, u.Phone, u.Name, u.CoName, u.CoPhone, u.pCustomUser, u.Birthday, u.QQ, u.Email, u.SelfIntr };

users2:

var users2 = (from u1 in Users
             join u2 in distribs on u1.pDistribId equals u2.Id
             into temp
             from u3 in temp.DefaultIfEmpty()
             select new {
                 u1,
                 u3
             }).ToList()
             .Select(x => new {
                 x.u1.Id,
                 x.u1.UserName,
                 x.u1.pDistribId,
                 pUserName = x.u3 == null ? "" : x.u3.UserName,
                 x.u1.Phone,
                 x.u1.Name,
                 x.u1.pCustomUser,
                 x.u1.CoName,
                 x.u1.CoPhone,
                 x.u1.Birthday,
                 x.u1.QQ,
                 x.u1.Email,
                 x.u1.SelfIntr
             });


var c = users2.Count();

In this code Still report the same error：

var users2 = (from u1 in Users

Answer 1

The error DbComparisonExpression requires parameters of a comparable type likely relates to your use of .Equals() in where u.Equals("user") . It looks like u is a class, and you are comparing it to a string. You are comparing two different types.

Answer 2

对Linq查询结果使用ToList转换，sub linq也将被转换