无法使用EntityFramework添加FK [英] Cannot add FK using EntityFramework

问题描述

我正在使用 Entity Framework 学习 ASP.NET Core ，并且尝试在 UserDetails中添加 FK 表.这些是模型:

I'm learning ASP.NET Core with Entity Framework and I'm trying to add an FK in my UserDetails table. These are the model:

public class User
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }

    public virtual UserDetails UserDetail { get; set; }
}

public class UserDetails
{
    public string UserId { get; set; }
    public string Biography { get; set; }
    public string Country { get; set; }
    public Uri FacebookLink { get; set; }
    public Uri TwitterLink { get; set; }
    public Uri SkypeLink { get; set; }

    public virtual User UserKey { get; set; }
}

表 User 是 Master 表，其中包含应用程序中的所有注册用户(我使用的是AspNetCore.Identity).

The table User is the Master table which contains all the registered user in my application (I'm using AspNetCore.Identity).

实际上我想将属性 UserId 作为 FK 添加，该属性必须绑定 User 的 Id .因此，在 ApplicationContext 类中，我执行了以下操作:

Actual I want add as FK the property UserId which must bound the Id of User. So inside the ApplicationContext class I did the following:

public class DemoAppContext : IdentityDbContext<ApplicationUser>
{
   public DemoAppContext(DbContextOptions<DemoAppContext> options) : base(options)
   {
   }

   protected override void OnModelCreating(ModelBuilder builder)
   {
       builder.Entity<UserDetails>(entity =>
       {
           entity.Property(e => e.Biography).HasMaxLength(150);

           entity.Property(e => e.Country).HasMaxLength(10);

           entity.HasOne(d => d.UserKey)
                 .WithOne(p => p.UserDetail)
                 .HasForeignKey(d => d.???; <- problem here
       });
   }

   public DbSet<User> Users { get; set; }
   public DbSet<UserDetails> UserDetails { get; set; }
}

我重写了 OnModelCreating ，并使用为 UserDetails 表定义的 ModelBuilder 某些属性的 MaxLength .在 builder.Entity< UserDetails> 的最后一行中，我尝试指定 FK 与 HasOne =>创建关系.UserKey ，其中包含对象 User .这种关系是 1比1 ，因此我使用了 WithOne 并分配了 UserDetail ，其中包含了 UserDetails 对象.

I overrided the OnModelCreating and using the ModelBuilder I defined for UserDetails table the MaxLength of some properties. In the last line of builder.Entity<UserDetails> I tried to assign the FK creating the relationship with HasOne => UserKey which contains the object User. The relationship is 1 to 1 so I used WithOne and assigned UserDetail which contains the UserDetails object.

最后，我使用了 HasForeignKey ，但是当我键入 d.时，编译器没有显示任何属性.

At the end I used HasForeignKey but when I type d. the compiler doesn't show any properties.

我做错了什么?也许我把事情复杂化了?

What I did wrong? Maybe I overcomplicated the things?

对于任何错误，我们深表歉意.

Sorry for any errors, and thanks in advance for any explanation.

推荐答案

以下代码将起作用:

builder.Entity<UserDetails>(entity =>
{
    entity.Property(e => e.Biography).HasMaxLength(150);
    entity.Property(e => e.Country).HasMaxLength(10);

    entity.HasOne(d => d.UserKey)
              .WithOne(p => p.UserDetail)
          .HasForeignKey<UserDetails>(x => x.UserId);  //???; < -problem here
});

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