我的存储库中有一个要测试的方法
public User UpdateUserManyToMany(User user, List<Guid> manyToManyds)
{
var dbContext = _databaseContext as DbContext;
dbContext?.TryUpdateManyToMany(user.ManyToMany, manyToManyds
.Select(x => new ManyToMany{
OtherEntityId = x,
UserId = user.Id,
}), x => x.OtherEntityId);
return user;
}
我的ManyToMany实体：
public class ManyToMany
{
public Guid OtherEntityId { get; set; }
public OtherEntity OtherEntityId { get; set; }
public Guid UserId { get; set; }
public User User { get; set; }
}
我的TryUpdateManyToMany：
public static class ManyToManyExtensions
{
public static void TryUpdateManyToMany<T, TKey>(this DbContext db, IEnumerable<T> currentItems, IEnumerable<T> newItems, Func<T, TKey> getKey) where T : class
{
db.Set<T>().RemoveRange(currentItems.Except(newItems, getKey));
db.Set<T>().AddRange(newItems.Except(currentItems, getKey));
}
public static IEnumerable<T> Except<T, TKey>(this IEnumerable<T> items, IEnumerable<T> other, Func<T, TKey> getKeyFunc)
{
return items
.GroupJoin(other, getKeyFunc, getKeyFunc, (item, tempItems) => new { item, tempItems })
.SelectMany(t => t.tempItems.DefaultIfEmpty(), (t, temp) => new { t, temp })
.Where(t => ReferenceEquals(null, t.temp) || t.temp.Equals(default(T)))
.Select(t => t.t.item);
}
}
这是我的单元测试：
using (var context = new InMemoryDataBaseContext())
{
// Arrange
var repository = new UserRepository(context);
await context.Users.AddRangeAsync(GetUser());
await context.SaveChangesAsync();
// Act
var manyIds = new List<Guid>();
manyIds.Add(Guid.Parse("855d1a64-a707-40d5-ab93-34591a923abf"));
manyIds.Add(Guid.Parse("855d1a64-a787-40d9-ac93-34591a923abf"));
manyIds.Add(Guid.Parse("855d1a64-a707-41d9-ab93-39591a923abf"));
var user = new User();
var expected = repository.UpdateUserManyToMany(GetUser(), manyIds);
// Assert
}
但是我在测试中遇到以下错误：
Message:
System.InvalidOperationException : The instance of entity type 'ManyToMany' cannot be tracked because another instance with the same key value for {'UserId', 'OtherEntityId'} is already being tracked. When attaching existing entities, ensure that only one entity instance with a given key value is attached. Consider using 'DbContextOptionsBuilder.EnableSensitiveDataLogging' to see the conflicting key values.
Arborescence des appels de procédure:
IdentityMap`1.ThrowIdentityConflict(InternalEntityEntry entry)
IdentityMap`1.Add(TKey key, InternalEntityEntry entry, Boolean updateDuplicate)
IdentityMap`1.Add(TKey key, InternalEntityEntry entry)
NullableKeyIdentityMap`1.Add(InternalEntityEntry entry)
StateManager.StartTracking(InternalEntityEntry entry)
InternalEntityEntry.SetEntityState(EntityState oldState, EntityState newState, Boolean acceptChanges, Boolean modifyProperties)
InternalEntityEntry.SetEntityState(EntityState entityState, Boolean acceptChanges, Boolean modifyProperties, Nullable`1 forceStateWhenUnknownKey)
EntityGraphAttacher.PaintAction(EntityEntryGraphNode`1 node)
EntityEntryGraphIterator.TraverseGraph[TState](EntityEntryGraphNode`1 node, Func`2 handleNode)
EntityGraphAttacher.AttachGraph(InternalEntityEntry rootEntry, EntityState targetState, EntityState storeGeneratedWithKeySetTargetState, Boolean forceStateWhenUnknownKey)
DbContext.SetEntityState(InternalEntityEntry entry, EntityState entityState)
DbContext.RemoveRange(IEnumerable`1 entities)
InternalDbSet`1.RemoveRange(IEnumerable`1 entities)
ManyToManyExtensions.TryUpdateManyToMany[T,TKey](DbContext db, IEnumerable`1 currentItems, IEnumerable`1 newItems, Func`2 getKey) ligne 24
UserRepository.UpdateUserManyToMany(User user, List`1 manyToManyds) ligne 59
MyRepoUnitTest.MyTestMethod() ligne 102
--- End of stack trace from previous location where exception was thrown ```
答案 0 :(得分：0)
以下基于您提供的代码的示例程序可以正常运行：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
namespace IssueConsoleTemplate
{
public class User
{
public Guid Id { get; set; }
public string Name { get; set; }
public ICollection<ManyToMany> ManyToMany { get; set; } = new HashSet<ManyToMany>();
}
public class OtherEntity
{
public Guid Id { get; set; }
public string Name { get; set; }
public ICollection<ManyToMany> ManyToMany { get; set; } = new HashSet<ManyToMany>();
}
public class ManyToMany
{
public Guid OtherEntityId { get; set; }
public Guid UserId { get; set; }
public OtherEntity OtherEntity { get; set; }
public User User { get; set; }
}
public class Context : DbContext
{
public DbSet<OtherEntity> OtherEntities { get; set; }
public DbSet<User> Users { get; set; }
public DbSet<ManyToMany> ManyToMany { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder
.UseSqlServer(@"Data Source=.\MSSQL14;Integrated Security=SSPI;Initial Catalog=So63077461")
.UseLoggerFactory(
LoggerFactory.Create(
b => b
.AddConsole()
.AddFilter(level => level >= LogLevel.Information)))
.EnableSensitiveDataLogging()
.EnableDetailedErrors();
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<OtherEntity>(
entity =>
{
entity.HasKey(e => e.Id);
entity.HasMany(e => e.ManyToMany)
.WithOne(e => e.OtherEntity)
.HasForeignKey(e => e.OtherEntityId);
entity.HasData(
new OtherEntity
{
Id = new Guid("855d1a64-a707-40d5-ab93-34591a923abf"),
Name = "Bicycle"
},
new OtherEntity
{
Id = new Guid("855d1a64-a787-40d9-ac93-34591a923abf"),
Name = "Bus"
},
new OtherEntity
{
Id = new Guid("855d1a64-a707-41d9-ab93-39591a923abf"),
Name = "Plane"
});
});
modelBuilder.Entity<User>(
entity =>
{
entity.HasKey(e => e.Id);
entity.HasMany(e => e.ManyToMany)
.WithOne(e => e.User)
.HasForeignKey(e => e.UserId);
});
modelBuilder.Entity<ManyToMany>(
entity =>
{
entity.HasKey(e => new {e.OtherEntityId, e.UserId});
});
}
}
public static class ManyToManyExtensions
{
public static void TryUpdateManyToMany<T, TKey>(this DbContext db, IEnumerable<T> currentItems, IEnumerable<T> newItems, Func<T, TKey> getKey) where T : class
{
db.Set<T>().RemoveRange(currentItems.Except(newItems, getKey));
db.Set<T>().AddRange(newItems.Except(currentItems, getKey));
}
public static IEnumerable<T> Except<T, TKey>(this IEnumerable<T> items, IEnumerable<T> other, Func<T, TKey> getKeyFunc)
{
return items
.GroupJoin(other, getKeyFunc, getKeyFunc, (item, tempItems) => new { item, tempItems })
.SelectMany(t => t.tempItems.DefaultIfEmpty(), (t, temp) => new { t, temp })
.Where(t => ReferenceEquals(null, t.temp) || t.temp.Equals(default(T)))
.Select(t => t.t.item);
}
}
internal class UserRepository
{
private readonly Context _databaseContext;
public UserRepository(Context context)
{
_databaseContext = context;
}
public User UpdateUserManyToMany(User user, List<Guid> manyToManyds)
{
var dbContext = _databaseContext as DbContext;
dbContext?.TryUpdateManyToMany(user.ManyToMany, manyToManyds
.Select(x => new ManyToMany{
OtherEntityId = x,
UserId = user.Id,
}), x => x.OtherEntityId);
return user;
}
}
internal static class Program
{
private static async Task Main()
{
//
// Operations with referential integrity intact:
//
using var context = new Context();
context.Database.EnsureDeleted();
context.Database.EnsureCreated();
// Arrange
var repository = new UserRepository(context);
await context.Users.AddRangeAsync(GetUser());
await context.SaveChangesAsync();
// Act
var manyIds = new List<Guid>
{
new Guid("855d1a64-a707-40d5-ab93-34591a923abf"),
new Guid("855d1a64-a787-40d9-ac93-34591a923abf"),
new Guid("855d1a64-a707-41d9-ab93-39591a923abf")
};
var expected = repository.UpdateUserManyToMany(GetUser(), manyIds);
}
private static User GetUser()
=> User;
private static readonly User User = new User
{
Id = new Guid("30c35d2e-77fd-480b-9974-6ebf037a8f86"),
Name = "John"
};
}
}
System.InvalidOperationException：无法跟踪实体类型'ManyToMany'的实例，因为已经跟踪了另一个具有相同'{'UserId'，'OtherEntityId'}'键值的实例。附加现有实体时，请确保仅附加一个具有给定键值的实体实例。考虑使用'DbContextOptionsBuilder.EnableSensitiveDataLogging'查看冲突的键值。
错误消息指出，您的ManyToMany条目中至少有一个已经存在于数据库中（存在一个具有相同的UserId和OtherEntityId组合的条目）。
您可以通过在用3个ID填充manyIds变量后直接运行以下代码来验证这一点：
var user = GetUser();
var alreadyExistingManyToMany = context.ManyToMany
.Where(m => m.UserId == user.Id &&
manyIds.Contains(m.OtherEntityId))
.ToList();
Debug.Assert(alreadyExistingManyToMany.Count == 0);