试试这个:

public class Team
{
    public int TeamId { get; set;} 
    public string Name { get; set; }

    public virtual ICollection<Match> HomeMatches { get; set; }
    public virtual ICollection<Match> AwayMatches { get; set; }
}

public class Match
{
    public int MatchId { get; set; }

    public int HomeTeamId { get; set; }
    public int GuestTeamId { get; set; }

    public float HomePoints { get; set; }
    public float GuestPoints { get; set; }
    public DateTime Date { get; set; }

    public virtual Team HomeTeam { get; set; }
    public virtual Team GuestTeam { get; set; }
}


public class Context : DbContext
{
    ...

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Match>()
                    .HasRequired(m => m.HomeTeam)
                    .WithMany(t => t.HomeMatches)
                    .HasForeignKey(m => m.HomeTeamId)
                    .WillCascadeOnDelete(false);

        modelBuilder.Entity<Match>()
                    .HasRequired(m => m.GuestTeam)
                    .WithMany(t => t.AwayMatches)
                    .HasForeignKey(m => m.GuestTeamId)
                    .WillCascadeOnDelete(false);
    }
}

主键由默认约定映射。每队必须有两套火柴。你不能让一个集合被两个fk引用。Match映射没有级联删除，因为它在这些自引用的多对多中不起作用。

你也可以试试这个:

public class Match
{
    [Key]
    public int MatchId { get; set; }

    [ForeignKey("HomeTeam"), Column(Order = 0)]
    public int? HomeTeamId { get; set; }
    [ForeignKey("GuestTeam"), Column(Order = 1)]
    public int? GuestTeamId { get; set; }

    public float HomePoints { get; set; }
    public float GuestPoints { get; set; }
    public DateTime Date { get; set; }

    public virtual Team HomeTeam { get; set; }
    public virtual Team GuestTeam { get; set; }
}

当您使FK列允许null时，您就打破了循环。或者我们只是在欺骗EF模式生成器。

在我的情况下，这个简单的修改解决了问题。

也可以在导航属性上指定ForeignKey()属性:

[ForeignKey("HomeTeamID")]
public virtual Team HomeTeam { get; set; }
[ForeignKey("GuestTeamID")]
public virtual Team GuestTeam { get; set; }

这样就不需要向OnModelCreate方法添加任何代码

这是因为级联删除默认启用。问题是，当您对实体调用delete时，它也会删除每个f键引用的实体。你不应该让'required'值为空来解决这个问题。一个更好的选择是删除EF Code First的Cascade删除约定:

modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>(); 

在映射/配置时，显式地指示何时对每个子节点执行级联删除可能更安全。的实体。

我知道这是一个几年前的帖子，你可以用上面的解决方案解决你的问题。然而，我只是想建议那些仍然需要使用InverseProperty的人。至少你不需要改变OnModelCreating中的任何东西。

下面的代码未经测试。

public class Team
{
    [Key]
    public int TeamId { get; set;} 
    public string Name { get; set; }

    [InverseProperty("HomeTeam")]
    public virtual ICollection<Match> HomeMatches { get; set; }

    [InverseProperty("GuestTeam")]
    public virtual ICollection<Match> GuestMatches { get; set; }
}


public class Match
{
    [Key]
    public int MatchId { get; set; }

    public float HomePoints { get; set; }
    public float GuestPoints { get; set; }
    public DateTime Date { get; set; }

    public virtual Team HomeTeam { get; set; }
    public virtual Team GuestTeam { get; set; }
}

你可以在MSDN: https://msdn.microsoft.com/en-us/data/jj591583?f=255&MSPPError=-2147217396#Relationships上阅读更多关于InverseProperty的信息

EF Core中的InverseProperty使解决方案简单而干净。

InverseProperty

所以理想的解决方案是:

public class Team
{
    [Key]
    public int TeamId { get; set;} 
    public string Name { get; set; }

    [InverseProperty(nameof(Match.HomeTeam))]
    public ICollection<Match> HomeMatches{ get; set; }

    [InverseProperty(nameof(Match.GuestTeam))]
    public ICollection<Match> AwayMatches{ get; set; }
}


public class Match
{
    [Key]
    public int MatchId { get; set; }

    [ForeignKey(nameof(HomeTeam)), Column(Order = 0)]
    public int HomeTeamId { get; set; }
    [ForeignKey(nameof(GuestTeam)), Column(Order = 1)]
    public int GuestTeamId { get; set; }

    public float HomePoints { get; set; }
    public float GuestPoints { get; set; }
    public DateTime Date { get; set; }

    public Team HomeTeam { get; set; }
    public Team GuestTeam { get; set; }
}

我知道这是一个很老的问题，但2021年来到这里的EF Core > 3解决方案对我来说很有效。

Make sure to make foreign keys nullable Specify default behavior on Delete public class Match { public int? HomeTeamId { get; set; } public int? GuestTeamId { get; set; } public float HomePoints { get; set; } public float GuestPoints { get; set; } public DateTime Date { get; set; } public Team HomeTeam { get; set; } public Team GuestTeam { get; set; } } protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<Match>() .HasRequired(m => m.HomeTeam) .WithMany(t => t.HomeMatches) .HasForeignKey(m => m.HomeTeamId) .OnDelete(DeleteBehavior.ClientSetNull); modelBuilder.Entity<Match>() .HasRequired(m => m.GuestTeam) .WithMany(t => t.AwayMatches) .HasForeignKey(m => m.GuestTeamId) .OnDelete(DeleteBehavior.ClientSetNull); }