我正在发送授权请求,在授权的方法 Controller 中,我尝试更新已通过授权的用户的实体,但出现错误:
无法跟踪实体类型“SUsers”的实例,因为已跟踪具有键值“{Id: 1}”的另一个实例。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。
使用的堆栈
asp core 2.2、spa、vue、pwa、jwt、automapper 8.8.4、Microsoft.EntityFrameworkCore 2.2.4
版本
- 网络核心2.2
- Microsoft.EntityFrameworkCore 2.2.4
- Microsoft.EntityFrameworkCore.InMemory 2.2.4
- Microsoft.EntityFrameworkCore.Design 2.2.4
- Microsoft.EntityFrameworkCore.SqlServer 2.2.4
0,DI
public static class StartupExtension
{
public static IServiceCollection AddDependencies(this IServiceCollection _iServiceCollection, IConfiguration AppConfiguration )
{
#region Data
string ids = System.Guid.NewGuid().ToString();
_iServiceCollection.AddDbContext<BaseDbContext, FakeDbContext>(opt =>
{
opt.UseInMemoryDatabase(ids);
});
_iServiceCollection.AddScoped<IBaseDbContext>(provider => provider.GetService<BaseDbContext>());
#endregion
#region AutoMapper
var config = new MapperConfiguration(cfg => {
cfg.AddMaps("PWSPA.WEB", "PWSPA.BLL");
});
config.AssertConfigurationIsValid();
#endregion
#region Repository
_iServiceCollection.AddScoped(typeof(IGenericRepository<>), typeof(GenericRepository<>));
_iServiceCollection.AddScoped<IUnitOfWork, UnitOfWork>();
#endregion
#region service
#region mapper service
_iServiceCollection.AddScoped(typeof(IGenericMapperService<,>), typeof(GenericMapperService<,>));
_iServiceCollection.AddScoped(typeof(IMapperService), typeof(MapperService));
#endregion
_iServiceCollection.AddScoped<IAuthService, AuthService>();
#endregion
return _iServiceCollection;
}
}
1。 API Controller
public class AuthController : BaseApiController
{
private readonly ILogger _log;
private readonly SecuritySettings _config;
private readonly IUserVerify _signInMgr;
private readonly IAuthService _iAuthService;
[AllowAnonymous]
[HttpPost("login")]
public IActionResult Login([FromBody] RequestTokenApiModel model)
{
try
{
SUsersDTO user = null;
user = _iAuthService.SingleOrDefault(u =>
u.WindowsLogin.ToLower() == "guest");
user.WindowsLogin = "guest";
/*
The instance of entity type 'SUsers' cannot be tracked
because another
instance with the key value '{Id: 1}' is already being
tracked. When
attaching existing entities, ensure that only one entity
instance with a
given key value is attached.
*/
countUpdate = _iAuthService.Update(user);
}
catch (ArgumentException ex)
{
return BadRequest(ex.Message);
}
catch (Exception ex)
{
_log.LogError(ex, ex.Message);
return StatusCode(500, ex.Message);
}
}
}
2。服务
public class AuthService : ServiceBase<SUsers, SUsersDTO>, IAuthService
{
public AuthService(IUnitOfWork uow, IMapperService MapperService) : base(uow, MapperService)
{
Repository.Query().Include(u => u.Role).Load();
}
...
}
public class ServiceBase<TModel, TModelDTO> : IGenericService<TModelDTO> where TModel : class where TModelDTO : class
{
private readonly IUnitOfWork db;
private readonly IMapperService _MapService;
private readonly IGenericRepository<TModel> genericRepository;
private readonly IGenericMapperService<TModel, TModelDTO> genericMapService;
public ServiceBase(IUnitOfWork uow, IMapperService iMapperService)
{
_MapService = iMapperService;
db = uow;
genericRepository = uow.Repository<TModel>();
genericMapService = _MapService.Map<TModel, TModelDTO>();
}
protected virtual Type ObjectType => typeof(TModel);
protected virtual IGenericRepository<TModel> Repository => genericRepository;
protected virtual IMapperService MapService => _MapService;
protected virtual IGenericMapperService<TModel, TModelDTO> Map => genericMapService;
protected virtual IUnitOfWork Database => db;
...
public int Update(TModelDTO entityDto)
{
var entity = Map.For(entityDto);
return Repository.Update(entity);
}
}
3。 repo 协议(protocol)
public class GenericRepository<TEntity> :
IGenericRepository<TEntity> where TEntity : class
{
private readonly IBaseDbContext _context;
private readonly IUnitOfWork _unitOfWork;
private readonly string errorMessage = string.Empty;
public GenericRepository(IBaseDbContext context, IMapper _iMapper) //: base(context, _iMapper)
{
_context = context;
_unitOfWork = new UnitOfWork(context, _iMapper);
}
public Type ObjectType => typeof(TEntity);
protected virtual IBaseDbContext DbContext => _context;
protected virtual DbSet<TEntity> DbSet => _context.Set<TEntity>();
...
public int Update(TEntity updated)
{
if (updated == null)
{
return 0;
}
DbSet.Attach(updated);
_context.Entry(updated).State = EntityState.Modified;
return Save();
}
...
private int Save()
{
try
{
return _unitOfWork.Commit();
}
catch (DbUpdateException e)
{
throw new DbUpdateException(e.Message, e);
}
}
4。工作单元
public class UnitOfWork : IUnitOfWork
{
private readonly IBaseDbContext _dbContext;
private readonly Dictionary<Type, object> _repositories = new Dictionary<Type, object>();
private readonly IMapper _iMapper;
public Dictionary<Type, object> Repositories
{
get => _repositories;
set => Repositories = value;
}
public UnitOfWork(IBaseDbContext dbContext, IMapper _iMapper)
{
_dbContext = dbContext;
this._iMapper = _iMapper;
}
public IGenericRepository<TEntity> Repository<TEntity>() where TEntity : class
{
if (Repositories.Keys.Contains(typeof(TEntity)))
{
return Repositories[typeof(TEntity)] as IGenericRepository<TEntity>;
}
IGenericRepository<TEntity> repo = new GenericRepository<TEntity>(_dbContext, _iMapper);
Repositories.Add(typeof(TEntity), repo);
return repo;
}
public EntityEntry<TEintity> Entry<TEintity>(TEintity entity) where TEintity : class
{
return _dbContext.Entry(entity);
}
...
}
存储库发生异常
public int Update(TEntity updated)
{
if (updated == null)
{
return 0;
}
/*
on line DbSet.Attach(updated) an exception occurs
*/
DbSet.Attach(updated);
_context.Entry(updated).State = EntityState.Modified;
return Save();
}
我认为这是由于使用存储库的服务中的映射造成的
public int Update(TModelDTO entityDto)
{
var entity = Map.For(entityDto);
return Repository.Update(entity);
}
重现步骤
- 克隆https://github.com/UseMuse/asp-core-2.2-clean.git
- 构建解决方案,启动 PWSPA.WEB 项目
- 登录:登录 - 访客,通过 - 任何图表
- 在 API Controller AuthController 中,方法 Login,异常行 90
预期行为:
实体更新
错误消息
无法跟踪实体类型“SUsers”的实例,因为已跟踪具有键值“{Id: 1}”的另一个实例。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。
堆栈跟踪
位于 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap1.ThrowIdentityConflict(InternalEntityEntry 条目)
在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.IdentityMap
1.Add(TKey 键,InternalEntityEntry 条目, bool updateDuplicate)
在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.StartTracking(InternalEntityEntry 条目)
在Microsoft.EntityFrameworkCore.ChangeTracking.Internal.InternalEntityEntry.SetEntityState(EntityState oldState,EntityState newState, bool acceptChanges)
在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.EntityGraphAttacher.PaintAction(EntityEntryGraphNode 节点, bool 力)
在 Microsoft.EntityFrameworkCore.ChangeTracking.Internal.EntityEntryGraphIterator.TraverseGraph[TState](EntityEntryGraphNode 节点,TState 状态,Func3 handleNode)
在 Microsoft.EntityFrameworkCore.DbContext.SetEntityState[TEntity](TEntity 实体,EntityState 实体状态)
在 D:\repos\asp-core-2.2-clean2\PWSPA.DAL\Repositories\GenericRepository.cs 中的 PWSPA.DAL.Repositories.GenericRepository
1.Update(TEntity Updated):第 99 行
在 D:\repos\asp-core-2.2-clean2\PWSPA.BLL\Services\ServiceBase.cs 中的 PWSPA.BLL.Services.ServiceBase`2.Update(TModelDTOEntityDto):第 208 行
在 D:\repos\asp-core-2.2-clean2\PWSPA.WEB\API\AuthController.cs 中的 PWSPA.API.Controllers.AuthController.Login(RequestTokenApiModel 模型):第 90 行
最佳答案
您在这里犯了一个菜鸟错误,本质上只是转储您能想到的所有信息,但具有讽刺意味的是,您错过了唯一真正重要的部分:_iAuthService
背后的代码。仅发布与问题直接相关的代码。如果我们需要其他东西,我们可以随时提出要求。并且,在这方面,发布与该问题直接相关的所有代码。如果错误是由您编写的自定义服务类引起的,请发布该服务类。
也就是说,您遇到的错误可归结为以下情况。在某些时候,您查询一个实体,该实体会将其添加到上下文的对象跟踪中。然后,您稍后尝试更新该实体的非跟踪版本,而不是您查询的版本。从模型绑定(bind)器接收它(即它是操作上的参数),使用 new 实例化它,或者简单地使用上下文的不同实例来检索它(并保存它)可能会发生这种情况到另一个实例)。
根据您提供的代码,我的钱在最后一个。您可能没有在服务类中正确处理上下文,并且您正在从上下文的一个实例获取要修改的实体,并尝试使用上下文的不同实例来更新它。您的上下文应该始终被注入(inject),以确保您在整个生命周期(请求)中始终使用相同的实例。换句话说,如果您正在执行 using (var context = new MyContext())
或任何 new MyContext()
,那就是您的问题。
关于c# - 无法跟踪实体类型 ''的实例,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/56582494/