AspNet EF6 - 实体类型没有定义键

Question

所以我更改了我的数据库并重新制作了它们。我遵循了 EF6 教程，但在尝试创建带有视图的控制器时遇到了这个错误。我对错误做了一些研究，人们说要添加数据注释，我尝试了 [Key]，但我一直遇到同样的错误。不确定我是否忘记了什么？谢谢！

"There was an error running the selected code generator: 'Unable to retrieve metadata for 'LinkDB.Models.Identifier.' Unable to determine the principal end of an association between the type 'LinkDB.Models.Identifier' and 'LinkDB.Models.Identity'. The principal end of this association must be explicity configured using either the relationship fluent API or data annotation.'

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;

namespace LinksDB.Models
{
    public class Identity
    {
        [Key]
        public int ID { get; set; }

        public int IdentifierID { get; set; }
        public string contact { get; set; }
        public string contactname { get; set; }
        public string price { get; set; }

        public virtual ICollection<Link> Links { get; set; }
        public virtual Identifier Identifiers { get; set; }
        public virtual Metric Metrics { get; set; }
    }
}

 using System;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;


namespace LinksDB.Models
{
    public class Identifier
    {
        [Key]
        public int ID { get; set; }
        public string domain { get; set; }

        public virtual ICollection<Link> Links { get; set; }
        public virtual Identity Identitys { get; set; }
        public virtual Metric Metrics { get; set; }

    }
}

using LinksDB.Models;
using System.Data.Entity;
using System.Data.Entity.ModelConfiguration.Conventions;

namespace LinksDB.DAL
{
    public class LinkData : DbContext
    {

        public LinkData() : base("LinkData")
        {
        }
        public DbSet<Identifier> Identifiers { get; set; }
        public DbSet<Identity> Identitys { get; set; }
        public DbSet<Link> Links { get; set; }
        public DbSet<Metric> Metrics { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
        }
    }
}

Answer 1

好的，如果您想要在身份和标识符之间建立 1:1 关系，那么这些模型应该如下所示，其中子项（标识符）使用 IdentityId 作为 PK 和 FK。您也可以使用流畅的代码来做到这一点。从这个开始，然后添加您的指标和链接关系。

public class Identity
{
    [Key]
    public int ID { get; set; }

    public string contact { get; set; }
    public string contactname { get; set; }
    public string price { get; set; }

    public virtual Identifier Identifier { get; set; }
}

public class Identifier
{
    [Key, ForeignKey("Identity")]
    public int IdentityID { get; set; }

    public string domain { get; set; }

    public virtual Identity Identity { get; set; }
}

例子here

AspNet EF6 - 实体类型没有定义键

AspNet EF6 - Entity type has no key defined

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