从具有外键mvc 5的表中删除。

Question

我有两张桌子升降机

public class Lift()
{
  [Key]
  public int LiftID { get; set; }
  public string StartPoint { get; set; }
  public virtual List<RequestLift> requestLifts { get; set; }
}

然后是RequestLift表

public class RequestLift()
{
  [Key]
  public int RequestLiftID { get; set; }
  public int DriverID { get; set; }
}

DriverID是LiftID的外键。我希望能够删除电梯，因此请求升降机。在我的控制器中我有

[HttpGet]
        public ActionResult Delete(int id)
        {
            //if (id == null)
            //{
            //    return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            //}

            Lift lift = db.Lifts.Find(id);
            db.Lifts.Remove(lift);
            db.SaveChanges();
            return RedirectToAction("Index");
        }

然后在我的身份模型中

    public DbSet<Lift> Lifts { get; set; }
    public DbSet<WeeklyLift> weeklyLifts { get; set; }
    public DbSet<RequestLift> requestLifts { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Lift>()
          .HasOptional(l => l.requestLifts)
          .WithMany()
          .WillCascadeOnDelete(true);
        base.OnModelCreating(modelBuilder)
    }

但是，当我尝试删除两个表中包含键的内容时，会发生未处理的异常错误。