我有一个最初为 .NET 6 编写并使用 WebAssembly 的 Blazor 项目。
我已将其迁移到 .NET 8 - 仍然使用 WebAssembly，但已决定使用新的“InteractiveServer”渲染模式将许多“管理”功能移回服务器。这很适合并且效果很好。
我有很多与服务器（标准控制器）交互的服务，但为了使交互式服务器和 WebAssembly 都能正常工作，有必要将服务放入接口中，并在服务器上拥有类似的（接口）服务来绕过控制器直接进入数据访问层。
这项工作大部分是我完成的。但我必须做的一件事是将应用程序
DbContextDbContextFactory在上一个操作完成之前，在此上下文实例上启动了第二个操作。这通常是由于不同线程同时使用同一个 DbContext 实例导致的
我现在收到这样的 EF Core 跟踪错误：
无法跟踪实体类型“ApplicationUser”的实例，因为已跟踪具有相同键值 {'Id'} 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。考虑使用“DbContextOptionsBuilder.EnableSensitiveDataLogging”来查看冲突的键值
奇怪的是我从服务中调用 DAL，如下所示：
public async Task<ApplicationUserDTO> UpdateUser(ApplicationUserDTO user)
{
using var _dbContext = _dbContextFactory.CreateDbContext();
bool updatingcurrrentuser = false;
if (user.Id == CurrentUser.Id)
updatingcurrrentuser = true;
InfoBool? result = new();
bool userisAdmin = false;
ApplicationUser? loggedinUser = await _userLib.GetLoggedInUser(_dbContext);
if (_userLib.UserIsAdmin(loggedinUser))
{
userisAdmin = true; // This is to allow admin users to add paper tickets which can override the ticket price check
}
if (userisAdmin || (user.Id == loggedinUser.Id)) // If the logged in user is an admin or the person edited then allow the update
{
// ApplicationUser sentUser = new ApplicationUser();
// _mapper.Map(sentUserDTO, sentUser);
result = await _userLib.UpdateUser(_userManager, _dbContext, user, user.Roles, userisAdmin);
}
// ... more stuff
}
UpdateUserpublic async Task<InfoBool> UpdateUser(
UserManager<ApplicationUser> userManager,
RGDbContext context,
ApplicationUserDTO user,
List<string> Roles = null,
bool userisadmin = false)
{
// First check if its there
// ApplicationUser founduser = await userManager.FindByNameAsync(user.UserName);
ApplicationUser? founduser = await context.Users
.Include(x => x.Address)
//.Include(x => x.Player) // Don't need the player
//.ThenInclude(y => y.Coins)
.SingleOrDefaultAsync(x => x.UserName == user.UserName);
if (founduser == null)
{
return new InfoBool(false, "User to update not found");
}
if (founduser.Address != null && user.Address != null && user.Address.Id == 0)
{
// If there is an address but the client sends it with a zero id - to detect a client error
return new InfoBool(false, "Address Id mismatch Error");
}
_mapper.Map(user, founduser);
_mapper.Map(user.Address, founduser.Address);
IList<string> currentroles = await GetRolesAsync(context, founduser.Id);
// First check for changed roles
// Creates a list of the roles in Roles to add not in current roles
List<string> newrolestoadd = Roles.Except(currentroles).ToList();
// Create a list of the roles in current roles to remove not in roles
List<string> rolestoremove = currentroles.Except(Roles).ToList();
if (newrolestoadd.Count() > 0) // There are some
{
// If a player role has been added
if (!currentroles.Contains(Enums.AllowedRoles.Player.ToString())
&& Roles.Contains(Enums.AllowedRoles.Player.ToString()))
{
founduser.IsPlayer = true;
}
if (!userisadmin && newrolestoadd.Contains(Enums.AllowedRoles.Administrator.ToString()))
{
// Just a check that any user adding an adminrole is already an admin
newrolestoadd.Remove(Enums.AllowedRoles.Administrator.ToString()); //Not allowed
// TODO: add a log record here to indicate a possible security risk
}
await AddUsertoRoles(userManager, founduser, newrolestoadd);
}
// Remove roles
if (rolestoremove.Count() > 0)
{
if (!userisadmin && rolestoremove.Contains(Enums.AllowedRoles.Administrator.ToString()))
{
// Only an admin can remove an admin
rolestoremove.Remove(Enums.AllowedRoles.Administrator.ToString());
}
await RemoveUserFromRoles(userManager, founduser, rolestoremove);
}
// Now check the address (we don't check for changes IN the address, just if it exists.
try
{
context.Entry(founduser).State = EntityState.Modified;
await context.SaveChangesAsync();
}
catch (Exception e)
{
return new InfoBool(false, e.Message);
}
return new InfoBool(true, "User update successful");
}
最初在添加或删除角色时，跟踪错误发生在 UserLib 的内部：
private async Task<IdentityResult> RemoveUserFromRoles(
UserManager<ApplicationUser> userManager,
ApplicationUser User,
IList<string> RolesToRemove)
{
try
{
IdentityResult result = IdentityResult.Success;
foreach (string role in RolesToRemove)
{
if (await userManager.IsInRoleAsync(User, role))
{
result = await userManager.RemoveFromRoleAsync(User, role);
if (!result.Succeeded) //If not successful the bail with the error
{
return result;
}
}
}
return result;
}
catch (Exception ex)
{
Console.WriteLine( ex.Message );
return IdentityResult.Failed(new IdentityError() { Code="Exception", Description=$"{ex.Message}"});
}
}
我在这里仅使用 userManager，正如您在这些函数中所看到的，上下文和 userMananger 都在顶部（UpdateUser）函数中传入。奇怪的是，当我从控制器调用相同的函数时。它不会发生并且工作正常。 为了完整起见，控制器代码是：
public async Task<ActionResult<InfoBool>> UpdateUser(ApplicationUserDTO sentUserDTO)
{
if (!ModelState.IsValid)
{
return BadRequest(ModelState);
}
// Get the logged in user.
ApplicationUser loggedinUser = await _userManager.GetUserAsync(User).ConfigureAwait(false);
IList<string> roles = await _userManager.GetRolesAsync(loggedinUser);
bool userisadmin = false;
if (roles.Contains(Enums.AllowedRoles.Administrator.ToString())) userisadmin = true;
if (userisadmin || (sentUserDTO.Id == loggedinUser.Id)) // If the logged in user is an admin or the person edited then allow the update
{
return await _userlib.UpdateUser(_userManager, _context, sentUserDTO, sentUserDTO.Roles, userisadmin);
}
return Unauthorized();
}
我的猜测是，我在服务器端服务代码中使用 contextFactory 意味着它与 userManager 使用的上下文不同。 然而，控制器中的上下文只是启动时在program.cs 中创建的标准上下文。我在这里缺少什么？
编辑 添加 GetLoggedInUser 函数。我认为您不能搜索 AsNotTracked 项目，但将其分离应该可以，不是吗？
///
/// Uses the ihttpContext to get the current user without using user manager
/// DO NOT USE the value returned to update the DB as it has been detached from the context
///
public async Task<ApplicationUser> GetLoggedInUser(RGDbContext context)
{
var claimslist = _httpContextAccessor.HttpContext.User.Claims.ToList();
string userId = claimslist.Find(x => x.Type.EndsWith("nameidentifier")).Value;
ApplicationUser? user = await context.Users.FindAsync(userId);
if (user == null) return null;
foreach (var claim in claimslist)
{
if (claim.Type.EndsWith("role"))
{
user.Roles.Add(claim.Value);
}
}
context.Entry(user).State = EntityState.Detached;
return user;
}
在代码中，您在
UpdateUser_userLib.GetLoggedInUser_userLib.UpdateUser在
UpdateUserUserManagerRemoveUserFromRoles控制器为何工作？ 不知道，但没有迹象表明
_context如何解决。 整理一下你的逻辑。
不要传递上下文。 打开和关闭上下文作为方法内的事务。
在
UpdateUser在您的
_userLib在
_userLib.UpdateUserUserManager