Question

我想在MyActivity应用中创建的标准ApplicationUser对象中添加ASP.NET webforms对象列表：

public class ApplicationUser : IdentityUser
{
    public ICollection<MyActivity> Activities { get; set; } // Added that

    public ClaimsIdentity GenerateUserIdentity(ApplicationUserManager manager)
    {
        // Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
        var userIdentity = manager.CreateIdentity(this, DefaultAuthenticationTypes.ApplicationCookie);
        // Add custom user claims here
        return userIdentity;
    }

    public Task<ClaimsIdentity> GenerateUserIdentityAsync(ApplicationUserManager manager)
    {
        return Task.FromResult(GenerateUserIdentity(manager));
    }
}

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
    public ApplicationDbContext()
        : base("DefaultConnection", throwIfV1Schema: false)
    {
    }

    public static ApplicationDbContext Create()
    {
        return new ApplicationDbContext();
    }
}

我将MyActivity类定义为：

public class MyActivity
{
    public Guid Id { get; set; }
    public ApplicationUser User { get; set; }
    public string SomeProp { get; set; }
}

然后我执行了＃34; add-migration UserActivities＆＃34;和＆＃34; update-database＆＃34;。我创建了一个MyActivities表，其中包含一个User_Id外键，引用了AspNetUsers.Id。一切都很好。

但现在，当我尝试添加活动时：

using (var db = new ApplicationDbContext())
{
    var manager = Context.GetOwinContext().GetUserManager<ApplicationUserManager>();
    var currentUser = manager.FindById(User.Identity.GetUserId());
    currentUser.Activities.Add(new MyActivity { SomeProp = "1" });
    db.SaveChanges();
}

我得到NullReferenceException（currentUser.Activities为空）。

有什么问题？

Answer 1

FindById默认不会返回您的自定义子集合。您可以直接访问Users表：

var currentUser = db.Users.Include(u => u.Activities).First(u => u.Id == manager.FindById(User.Identity.GetUserId());

更好的方法是实现自己的UserStore，覆盖类似于此的FindById：Custom entities with asp net identity (one-to-many)

ASP.NET将列表添加到ApplicationUser

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