sql-server - 基于外键 EF 的主键

Question

一开始我尝试过，如下，但仍然没有结果:

• Defining two foreign keys as primary key in Entity Framework
• Entity Framework Two foreign keys as primary key

这是我的实体:

public class Passage
{
        [Key, ForeignKey("FromID")]
        public Localization From { get; set; }

        public int ToID { get; set; }

        [Key, ForeignKey("ToID")]
        public Localization To { get; set; }

        [Required]
        public string HourForm { get; set; }

        [Required]
        public string HourTo { get; set; }

        [Required]
        public int Seats { get; set; }

        [Required]
        public char Weekend { get; set; }

        public int? AdditinalTime { get; set; }

        public int FromID { get; set; }
}

我正在尝试基于两个外键创建主键。有错误

EntityType 'Passage' has no key defined. Define the key for this EntityType.

我做错了什么？

Answer 1

直接引用您的第一个链接:

“主键始终必须由实体类中的标量属性定义。您不能仅通过导航属性来引用 PK。”

因此，您需要将关键属性放在标量值上，而不是导航属性上。

public class Passage
{
    [Key, ForeignKey("From"), Column(Order = 0)]
    public int FromID { get; set; }

    public Localization From { get; set; }

    [Key, ForeignKey("To"), Column(Order = 1)]
    public int ToID { get; set; }

    public Localization To { get; set; }
}