EntityFramework种子AddOrUpdate与外键

Question

尝试首先使用实体​​框架和代码在ASP.NET Web应用程序中播种数据.我将此代码放在Seed()Configuration.cs文件的方法中.现在我正在研究解决方案的地址方面,我正在尝试将所有状态和县加载到系统中.

这是我的状态代码,工作得很好......

context.StateProvinces.AddOrUpdate(
    p => p.Abbreviation,
    new StateProvince { Abbreviation = "AL", Name = "Alabama" },
    new StateProvince { Abbreviation = "AK", Name = "Alaska" },
    new StateProvince { Abbreviation = "AZ", Name = "Arizona" },
    ....
);

我该如何使用该AddOrUpdate()功能context.Counties？这就是我的County对象的样子.

public class County
{
    public int CountyId { get; set; }
    public int StateProvinceId { get; set; }
    public String Name { get; set; }

    [ForeignKey("StateProvinceId")]
    public virtual StateProvince StateProvince { get; set; }
}

虽然我可以简单地复制我对国家做的格式,但我们知道县名在全国范围内重复使用.所以我不能简单地c => c.Name用作现有支票.我可以使用name和StateProvinceId字段吗？

Answer 1

为什么不将县添加到州,而不是反过来呢？

如果你不能这样做,那么你可以修改你的以下内容:

var al = new StateProvince { Abbreviation = "AL", Name = "Alabama" },
var ak = new StateProvince { Abbreviation = "AK", Name = "Alaska" },
var ar = new StateProvince { Abbreviation = "AZ", Name = "Arizona" },

context.StateProvinces.AddOrUpdate(
    p => p.Abbreviation,
    al,
    ak,
    ar
);

context.SaveChanges();

context.Counties.Add(new County() { Name = "Something", StateProvince = al });

// DONT CALL SAVE, Initializer needs something to do or it complains