Question

可能重复：
LINQ to SQL: Return anonymous type?

我对List＆lt;＆gt;使用什么返回类型？在linq加入？我正在加入下面的多个表格，我收到错误'Cannot implicitly convert type System.Collections.Generic.List<AnonymousType#1> to System.Collections.Generic.List<CargoTanksDAL.aspnet_Users>

    public List<> GetAspnetUsersWithMembershipAndCompany()
    {

        using (DevCargoEntities db = new DevCargoEntities())
        {
            var users = from u in db.aspnet_Users
                        join mem in db.aspnet_Membership on u.UserId equals mem.UserId
                        join cl in db.CT_CompanyLogIn on u.UserName equals cl.UserLogIn
                        join companies in db.CT_Companies on cl.CompanyID equals companies.CompanyID
                        select new
                        {
                            u.UserId,
                            u.UserName,
                            mem.Email,
                            mem.IsLockedOut,
                            mem.IsApproved,
                            mem.CreateDate,
                            companies.CompanyName
                        };

            return users.ToList();
        }
    }

Answer 1

无。此处的连接无关紧要，选择确实如此，您选择匿名类型。您无法返回匿名类型。最好创建一个包含要返回的属性的新类，并实例化该类型。

理论上你可以返回动态或对象，但这是你真正不想走的路径。相信我。

Answer 2

我会为这个用户创建一个新类..

public class SomeKindOfUser
{
    public int UserId { get; set; }
    public string UserName { get; set; }
    public string Email { get; set; }
    public bool IsLockedOut { get; set; }
    public bool IsApproved { get; set; }
    public DateTime CreateDate { get; set; }
    public string CompanyName { get; set; }
}

现在你可以使用

public List<SomeKindOfUser> GetAspnetUsersWithMembershipAndCompany()

然后在选择：

select new SomeKindOfUser
                        {
                            UserId = u.UserId,
                            UserName = u.UserName,
                            Email = mem.Email,
                            IsLockedOut = mem.IsLockedOut,
                            IsApproved = mem.IsApproved,
                            CreateDate = mem.CreateDate,
                            CompanyName = companies.CompanyName
                        };

linq join返回类型

2 个答案: