userManager.CreateAsync System.ObjectDisposedException未处理

Question

我们正在尝试在ASP.Net 5项目中使用Microsoft帐户身份验证.我们不需要本地身份验证,也不需要用户名.

在用于Web应用程序的ASP.Net 5模板中,在使用外部提供程序登录后,控件将返回到ExternalLoginCallbackAccountController中.

如果用户未在本地注册,ExternalLoginCallback则将用户返回到注册屏幕.我试图修改ExternalLoginCallback为自动注册新用户,如下所示.

        public async Task<IActionResult> ExternalLoginCallback(string returnUrl = null)
    {
        var info = await _signInManager.GetExternalLoginInfoAsync();
        if (info == null)
        {
            return RedirectToAction(nameof(Login));
        }

        // Sign in the user with this external login provider if the user already has a login.
        var result = await _signInManager.ExternalLoginSignInAsync(info.LoginProvider, info.ProviderKey, isPersistent: false);
        if (result.Succeeded)
        {
            _logger.LogInformation(5, "User logged in with {Name} provider.", info.LoginProvider);
            return RedirectToLocal(returnUrl);
        }
        if (result.RequiresTwoFactor)
        {
            return RedirectToAction(nameof(SendCode), new { ReturnUrl = returnUrl });
        }
        if (result.IsLockedOut)
        {
            return View("Lockout");
        }
        else
        {
            // If the user does not have an account, then ask the user to create an account.
            //ViewData["ReturnUrl"] = returnUrl;
            //ViewData["LoginProvider"] = info.LoginProvider;
            //var email = info.ExternalPrincipal.FindFirstValue(ClaimTypes.Email);
            //return View("ExternalLoginConfirmation", new ExternalLoginConfirmationViewModel { Email = email });

            // The user has not previously logged in with an external provider. Create a new user.
            CreateUser(info);
            return RedirectToLocal(returnUrl);
        }
    }

CreateUser实现从ExternalLoginConfirmationWeb应用程序的ASP.Net 5模板中显示的复制代码.

        private async void CreateUser(ExternalLoginInfo info)
    {
        var email = info.ExternalPrincipal.FindFirstValue(ClaimTypes.Email);
        var user = new ApplicationUser { UserName = email, Email = email };
        var result = await _userManager.CreateAsync(user);
        if (result.Succeeded)
        {
            result = await _userManager.AddLoginAsync(user, info);
            if (result.Succeeded)
            {
                await _signInManager.SignInAsync(user, isPersistent: false);
                _logger.LogInformation(6, "User created an account using {Name} provider.", info.LoginProvider);
            }
        }
        AddErrors(result);
    }

线路上出现错误

var result = await _userManager.CreateAsync(user);

错误是

System.ObjectDisposedException was unhandled Message: An unhandled exception of type 'System.ObjectDisposedException' occurred in mscorlib.dll. Additional information: Cannot access a disposed object.

我已经重新启动了我的机器,以防它只是"其中一件事",但错误再次发生.

Answer 1

使用的async void方法是很少一个好主意,是引入怪异的竞争条件像您遇到的一个最好的方式,因为你的CreateUser方法不返回的任务,它不能被期待已久ExternalLoginCallback,并请求之前完成CreateUser有执行数据库操作的时间(当请求完成时,DI系统调用Dispose范围内的依赖关系,如您的EF上下文).

更新您的CreateUser方法以返回Task并等待它ExternalLoginCallback,它应该工作:

await CreateUser(info);