无法确定导航所代表的关系属性

Question

我在尝试保存实体时收到客户端错误。 2 个表同时具有一对多和一对零关系，这会导致以下错误：

Unable to determine the relationship represented by navigation property 'Group.LockedByUser' of type 'User'. Either manually configure the relationship, or ignore this property using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating

这些是我当前的上下文：

用户实体

public class User
{
    [Key]
    public int UserId { get; set; }
    public string Username { get; set; }
    public int GroupId { get; set; }

    public Group GroupThisUserBelongsTo { get; set; }
    public ICollection<Group> GroupsLockedByThisUser { get; set; }
    public ICollection<Config> Configs { get; set; }
}

团体实体

public class Group
{ 
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int GroupId { get; set; }
    public string GroupName { get; set; }
    public int? LockedByUserId { get; set; }

    public User LockedByUser { get; set; }
    public ICollection<User> Users { get; set; }
}

DbContext1 提取

modelBuilder.Entity<Group>(entity =>
        {
            entity.HasOne(d => d.LockedByUser)
                .WithMany(p => p.GroupsLockedByThisUser)
                .HasForeignKey(d => d.LockedByUserId);
        }

modelBuilder.Entity<User>(entity =>
        {
            entity.HasOne(d => d.GroupThisUserBelongsTo)
                .WithMany(p => p.Users)
                .HasForeignKey(d => d.GroupId)
                .OnDelete(DeleteBehavior.ClientSetNull);
        });

配置实体

public class Config
{
    [Key]
    public int ConfigId { get; set; }
    public int UserId { get; set; }
    public string Config { get; set; }

    public User User { get; set; }
}

DbContext2 提取

 modelBuilder.Entity<Config>(entity =>
        {
            entity.HasOne(d => d.User)
                .WithMany(p => p.Configs)
                .HasForeignKey(d => d.UserId);
        });

产生错误的代码如下：

var config = new Config {
            UserId = 123456,
            Config = "test"
        };

        _dbContext2.Config.Add(config);
        _dbContext2.SaveChanges();

我真的不明白为什么在尝试保存该实体时出现客户端错误。错误甚至不是来自我试图保存的上下文。

我的外键设置正确吗？

Group 有很多 User - User 有一个 Group (FK GroupId)
User 锁定零个或多个 Group (FK LockedByUserId)
Config 有一个 User (FK UserId)

Answer 1

已尝试重现错误。没有复现：

using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.ComponentModel.DataAnnotations.Schema;
using System.ComponentModel.DataAnnotations;
//using Microsoft.Samples.EFLogging;
using System.Data.SqlClient;
using System.Xml.Linq;
using System.Threading.Tasks;

namespace EFCore2Test
{

    public class User
    {
        [Key]
        [DatabaseGenerated( DatabaseGeneratedOption.None)]
        public int UserId { get; set; }
        public string Username { get; set; }
        public int GroupId { get; set; }

        public Group GroupThisUserBelongsTo { get; set; }
        public ICollection<Group> GroupsLockedByThisUser { get; set; }

        public ICollection<Config> Configs { get; set; }
    }
    public class Group
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int GroupId { get; set; }
        public string GroupName { get; set; }
        public int? LockedByUserId { get; set; }

        public User LockedByUser { get; set; }
        public ICollection<User> Users { get; set; }
    }

    public class Config
    {
        [Key]
        public int ConfigId { get; set; }
        public int UserId { get; set; }
        public string ConfigName { get; set; }

        public User User { get; set; }
    }

    public class Db : DbContext
    {
        public DbSet<User> Users { get; set; }
        public DbSet<Group> Groups { get; set; }

        public DbSet<Config> Configs { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Group>()
                .HasOne(d => d.LockedByUser)
                .WithMany(p => p.GroupsLockedByThisUser)
                .HasForeignKey(d => d.LockedByUserId);            

            modelBuilder.Entity<User>()
                .HasOne(d => d.GroupThisUserBelongsTo)
                .WithMany(p => p.Users)
                .HasForeignKey(d => d.GroupId)
                .OnDelete(DeleteBehavior.ClientSetNull);

            modelBuilder.Entity<Config>()
                .HasOne(d => d.User)
                .WithMany(p => p.Configs)
                .HasForeignKey(d => d.UserId);            

            base.OnModelCreating(modelBuilder);
        }
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlServer("Server=(local);Database=EFCoreTest;Trusted_Connection=True;MultipleActiveResultSets=true");
            base.OnConfiguring(optionsBuilder);
        }
    }

    class Program
    {   

        static void Main(string[] args)
        {            
            using (var db = new Db())
            {
                db.Database.EnsureDeleted();

                db.Database.EnsureCreated();
                //db.ConfigureLogging(s => Console.WriteLine(s));

                var g = new Group()
                {
                    GroupName = "G"
                };

                var u = new User()
                {
                    UserId = 123456,
                    GroupThisUserBelongsTo = g
                };                

                db.Users.Add(u);
                db.SaveChanges();

                g.LockedByUser = u;
                db.SaveChanges();

            }

            using (var db = new Db())
            {
                var config = new Config
                {
                    UserId = 123456,
                    ConfigName = "test"
                };

                db.Configs.Add(config);
                db.SaveChanges();
            }


            Console.WriteLine("Hit any key to exit");
            Console.ReadKey();
        }
    }
}

Answer 2

如所述，我需要复制共享关系。

当使用 DbContext2 时，User 和 Group 之间的关系未定义。

我可以通过使用单个上下文或让上下文继承定义所有共享关系的主上下文来解决我的问题。

无法确定导航所代表的关系属性

Unable to determine the relationship represented by navigation property

c#

entity-framework

ef-core-2.0