c# - 我收到错误 'EntityType has no key defined'，即使我在模型和数据库中都定义了一个键

Question

I've been following this tutorial关于如何在 MVC 中处理多个表，我在尝试为索引创建 View (教程中的第 12 步)时遇到错误，指定“EntityType 没有定义键”。我能够找到的唯一解决方案是在模型类的主键成员之前放置一个 [Key] 属性。但是，当我尝试再次创建 View 时，出现了同样的错误。

Controller 代码

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Linq;
using System.Net;
using System.Web;
using System.Web.Mvc;
using RelationalDatabaseWebsite.Models;

namespace RelationalDatabaseWebsite.Controllers
{
    public class UsersTablesController : Controller
    {
        private ApprenticeTestEntities db = new ApprenticeTestEntities();

        public ActionResult Index()
        {
            UsersLogContext cs = new UsersLogContext();
            List<Log> logs = cs.Log.ToList(); 
            return View(logs);
        }

Log 模型的代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations.Schema;
using System.ComponentModel.DataAnnotations;



namespace RelationalDatabaseWebsite.Models
{
    [Table("LogTable")]
    public class Log
    {
        [Key]
        public int LogTableID { get; set; }

        public int UserID { get; set; }
        public string TimeLogged { get; set; }

        public virtual UsersTable Users { get; set; }
    }
}

用户模型代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations.Schema;
using System.ComponentModel.DataAnnotations;


namespace RelationalDatabaseWebsite.Models
{
    [Table("UsersTable")]
    public class Users
    {
        [Key]
        public int UserID { get; set; }

        public string FirstName { get; set; }
        public string Surname { get; set; }
        public string Password { get; set; }
        public string Salt { get; set; }
        public string PhoneNumber { get; set; }
        public string Email { get; set; }
        public bool IsAdmin { get; set; }

        public virtual ICollection<AddressTable> Address { get; set; }
        public virtual ICollection<DOBTable> DOB { get; set; }
        public virtual ICollection<LogTable> Log { get; set; }


    }
}

DbContext 模型

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Entity;

namespace RelationalDatabaseWebsite.Models
{
    public class UsersLogContext : DbContext 
    {
        public DbSet<Users> Users { get; set; }
        public DbSet<Log> Log { get; set; }

    }
}

用户数据库表

CREATE TABLE [dbo].[UsersTable](
    [UserID] [uniqueidentifier] NOT NULL,
    [FirstName] [varchar](50) NOT NULL,
    [Surname] [varchar](50) NOT NULL,
    [Password] [varchar](50) NOT NULL,
    [Salt] [varchar](50) NOT NULL,
    [PhoneNumber] [varchar](50) NULL,
    [Email] [nvarchar](50) NOT NULL,
    [IsAdmin] [bit] NOT NULL,
 CONSTRAINT [PK_UsersTable] PRIMARY KEY CLUSTERED 
(
    [UserID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

日志数据库表

CREATE TABLE [dbo].[LogTable](
    [LogTableID] [int] IDENTITY(1,1) NOT NULL,
    [UserID] [uniqueidentifier] NOT NULL,
    [TimeLogged] [datetime] NOT NULL,
 CONSTRAINT [PK_LogTable_1] PRIMARY KEY CLUSTERED 
(
    [LogTableID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
GO

ALTER TABLE [dbo].[LogTable]  WITH CHECK ADD  CONSTRAINT [FK_LogTable_UsersTable] FOREIGN KEY([UserID])
REFERENCES [dbo].[UsersTable] ([UserID])
GO

ALTER TABLE [dbo].[LogTable] CHECK CONSTRAINT [FK_LogTable_UsersTable]
GO

对于大量代码表示歉意，只是因为日志和用户表都出现了错误，我会把这两部分都记下来，以防各自的错误相互关联。

Answer 1

您的 Users 表的键类型为 uniqueidentifier 但您的代码模型的键类型为 int

[Key]
public int UserID { get; set; }

...

[UserID] [uniqueidentifier] NOT NULL,

尝试将用户模型中的键(及其在 Log 模型中的相关属性)更改为 Guid...

[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid UserID { get; set; }