所以我有这两个实体
public class Player
{
[Key]
public Guid Id { get; private set; }
public Guid ActiveGroupId { get; set; }
public virtual Group ActiveGroup { get; set; }
public virtual ICollection<Group> Groups { get; set; }
}
public class Group
{
[Key]
public Guid Id { get; private set; }
public string Name { get; set; }
public virtual ICollection<Player> Players { get; set; }
}
所以我现在想做的是在 Configuration.Seed 中,如果玩家有 ActiveGroup 并且还没有组。然后将活动组添加到 Player.Groups。现在我总是失败,错误 Multiplicity constraint violated. The role 'Player_Groups_Source' of the relationship 'Entities.Player_Groups' has multiplicity 1 or 0..1.
这就是我所做的
foreach (var player in context.Players.ToList())
{
var activeGroup = context.Groups.First(x => x.Id == player.ActiveGroupId);
player.Groups.Add(activeGroup);
}
context.SaveChanges();
我正在使用 EF 6.4.4 并在 mac 上运行它(如果有问题的话)。知道这种方法有什么问题吗?
答案 0 :(得分:1)
您需要确保您的多对多关系定义正确
public class PlayerMap : EntityTypeConfiguration<Player>
{
public PlayerMap()
{
HasMany(a => a.Groups)
.WithMany(a => a.Players);
}
}
然后需要初始化Groups的集合:
public class Player
{
[Key]
public Guid Id { get; private set; }
public Guid ActiveGroupId { get; set; }
public virtual Group ActiveGroup { get; set; }
public virtual ICollection<Group> Groups { get; set; } = new List<Group>();
}
然后您可以向玩家添加一个组。