实体框架 – 无法确定依赖操作的有效排序

public string Content { get; set; }

public Faq Reply { set; get; }

public int? ReplyId { get; set; }

public ICollection<Faq> Children { get; set; }

[ForeignKey("WriterId")]
public virtual UserProfile Writer { get; set; }

public virtual int? WriterId { get; set; }

public Status Status { get; set; }

[ForeignKey("DepartmentId")]
public virtual Department Department { get; set; }

public virtual int? DepartmentId { get; set; }

这是我的错误

Unable to determine a valid ordering for dependent operations. Dependencies may exist due to foreign key constraints,model requirements,or store-generated values.