EF One To Many Bug

Question

谁能告诉我我做错了什么？

当它到达db.SaveChanges（）时，我收到以下错误。

在模型生成期间检测到一个或多个验证错误：EntityType＆＃39; Order＆＃39;没有定义键。定义此EntityType的键。 Orders1：EntityType：EntitySet＆＃39; Orders1＆＃39;是基于类型＆＃39;订单＆＃39;没有定义键。

正如你所看到的，我并不想做任何复杂的事情，但是，我看不出我错过了什么。

Db背景：

public class NewOrderContext : DbContext
{
    public DbSet<NewServices.OrderEntity> Orders { get; set; }
    public DbSet<NewServices.OrderLineEntity> OrderLines { get; set; }
}

OrderEntity：

[Table("Order")]
public class OrderEntity
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }
    public int State { get; set; }
    public decimal Handling { get; set; }
    public int BuyerId { get; set; }
    public string ShippingAddresseeName { get; set; }
    public string ShippingAddressLine1 { get; set; }
    public string ShippingAddressLine2 { get; set; }
    public string ShippingCity { get; set; }
    public string ShippingRegion { get; set; }
    public string ShippingCountry { get; set; }
    public string ShippingPostalCode { get; set; }
    public DateTime Created { get; set; }
    public string TrackingRef { get; set; }
    public int OfferId { get; set; }

    public virtual ICollection<OrderLineEntity> OrderLines { get; set; }
}

OrderLineEntity：

[Table("OrderLine")]
public class OrderLineEntity
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }
    public string PartCode { get; set; }
    public decimal PartPrice { get; set; }
    public int OrderId { get; set; }

    [ForeignKey("OrderId")]
    public virtual Order Order { get; set; }
}

我在以下方法片段中使用上述内容：

using (var db = new NewOrderContext())
{
    var order = new OrderEntity
                {
                    OfferId = offerId,
                    ....
                    Created = DateTime.UtcNow
                };


    var lines = new List<OrderLineEntity>
                {
                    new OrderLineEntity
                    {
                        PartCode = offer.PartCode,
                        PartPrice = offer.PriceOffered
                    }
                };

    order.OrderLines = lines;
    db.Orders.Add(order);
    db.SaveChanges();
 ......
}