实体框架类实例化行为

Question

我面临一个问题，当我试图实例化任何类时，我的实体框架保持行为怪异。我正尝试使用默认的用户管理器行为将数据存储在我的数据库中。在将通知添加到应用程序用户类中可用的通知列表之前，我开始实例化新通知后，它会保留这些更改并处理来自实体框架的错误，指出存在多重性问题，如何告知实体框架不坚持变化一次，我在这里实例化一个类CF是我的控制器代码：

public string AddFriend(string AddedUserId) 
{ 
    var AddedUser = UserManager.FindById(AddedUserId); 
    var AddingUser = UserManager.FindById(User.Identity.GetUserId()); 
    var friendship = new Friend(AddingUser, AddedUser) { IsInvitation = true }; 
    AddingUser.Friends.Add(friendship); 
    AddedUser.Notifications.Add(new Notification(AddingUser, "Friend Invitation", 
        "The user " + AddingUser.FirstName + " " + AddingUser.LastName + 
        " Sent you a friend invitation", friendship)); 
    UserManager.Update(AddedUser); 
    UserManager.Update(AddingUser); 
    return "Friend was added successfully"; 
} 

我Notification类：

[Table("Notifications")] 
public class Notification 
{ 
    [Key] 
    public int NotificationId { get; set; } 
    public string Title { get; set; } 
    public string Content { get; set; } 
    [Required] 
    public ApplicationUser AssociatedUser { get; set; } 
    public Friend AssociatedFrienship { get; set; } 
    public GroupMember AssociatedGroup { get; set; } 
    public ChannelMember AssociatedChannel { get; set; } 
    public Message AssociatedMessage { get; set; } 
    public bool Consulted { get; set; } 

    public Notification() 
    { 
    } 

    public Notification(ApplicationUser associatedUser, string title, string content, Friend associatedFriend = null, GroupMember associatedGroup = null, ChannelMember associatedChannel = null, Message associatedMessage = null) 
    { 
     AssociatedUser = associatedUser; 
     Title = title; 
     Content = content; 
     AssociatedChannel = associatedChannel; 
     AssociatedGroup = associatedGroup; 
     AssociatedFrienship = associatedFriend; 
     AssociatedMessage = associatedMessage; 
     Consulted = false; 
    } 
} 

我ApplicationUser类：

public partial class ApplicationUser : IdentityUser 
{ 
    public virtual List<Notification> Notifications { get; set; } 
} 

我FluentAPI代码：

modelBuilder.Entity<Notification>() 
      .HasRequired(c => c.AssociatedUser) 
      .WithMany(c => c.Notifications); 

提前感谢！

Answer 1

您没有任何可连接的外键AssociatedUser。尝试添加一个属性以使用外键将Notification链接到ApplicationUser。像

public class Notification 
{ 
    //rest of properties 

    //change int to whatever type your primary key is in 
    //ApplicationUser class. I have Guid for example. 
    public int ApplicationUser AssociatedUserId {get;set;} 
} 

然后尝试修改这样的配置：除了

modelBuilder.Entity<Notification>() 
     .HasRequired(c => c.AssociatedUser) 
     .WithMany(c => c.Notifications) 
     .HasForeignKey(n=>n.AssociatedUserId);