Question

使用ASP.NET MVC5，EF6＆amp; Ninject as Backend，AngularJS作为基于令牌的auth（JWT）的前端。

我们最近必须在用户名中启用@chars。基于Startup.cs中的this answer（由Ninject注册码调用，见下文），我们更换了

UserManagerFactory = () => new ApplicationUserManager(new UserStore<IdentityUser>(new SecurityDbContext()));

与

var userManager = new ApplicationUserManager(new UserStore<IdentityUser>(new SecurityDbContext()));
var validator = new UserValidator<IdentityUser>(userManager)
{
    AllowOnlyAlphanumericUserNames = false
};
userManager.UserValidator = validator;
UserManagerFactory = () => userManager;

这允许用@符号注册用户名。但是，登录到应用程序（即使使用“普通”用户名）也会出现错误：虽然服务器启动后的第一次登录正常工作，但任何后续登录都会产生以下异常：

Cannot access a disposed object.
Object name: 'ApplicationUserManager'.

详细错误消息：

Source Error: 
Line 18:         public override async Task FindAsync(string userName, string password)
Line 19:         {
Line 20:             var result = await base.FindAsync(userName, password);
Line 21:             if (result == null)
Line 22:             {

Source File: 
xyz\Infrastructure\ApplicationUserManager.cs    Line: 20 

Stack Trace: 

[ObjectDisposedException: Cannot access a disposed object.Object name: 'ApplicationUserManager'.]   Microsoft.AspNet.Identity.UserManager`1.ThrowIfDisposed() +99   Microsoft.AspNet.Identity.d__15.MoveNext() +128   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52   System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() +24   xyz.Infrastructure.d__0.MoveNext() in xzy\Infrastructure\ApplicationUserManager.cs:20   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52   System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() +24   xyz.Infrastructure.d__0.MoveNext() in xyz\Infrastructure\ApplicationOAuthProvider.cs:39   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52   System.Runtime.CompilerServices.TaskAwaiter.GetResult() +21   Microsoft.Owin.Security.OAuth.d__3a.MoveNext() +862   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52   System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() +24   Microsoft.Owin.Security.OAuth.d__1e.MoveNext() +2335   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52   System.Runtime.CompilerServices.TaskAwaiter.GetResult() +21   Microsoft.Owin.Security.OAuth.d__0.MoveNext() +1728   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52   System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() +24   Microsoft.Owin.Security.Infrastructure.d__0.MoveNext() +664   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52   System.Runtime.CompilerServices.TaskAwaiter.GetResult() +21   Microsoft.Owin.Security.Infrastructure.d__0.MoveNext() +937   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52   System.Runtime.CompilerServices.TaskAwaiter.GetResult() +21   Microsoft.Owin.Security.Infrastructure.d__0.MoveNext() +937   System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +22   Microsoft.Owin.Host.SystemWeb.Infrastructure.ErrorState.Rethrow() +33   Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.StageAsyncResult.End(IAsyncResult ar) +150   Microsoft.Owin.Host.SystemWeb.IntegratedPipeline.IntegratedPipelineContext.EndFinalWork(IAsyncResult ar) +42   System.Web.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +415   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

我想这与Ninject有关，所以这里有更多背景：上面改变的代码是从NinjectWebCommon.cs调用的：

kernel.Bind<IUserService>()
    .To<UserService>()
    .WithConstructorArgument("userManager", Startup.UserManagerFactory());

Answer 1

问题：这是对象生命周期错误。

解决方案：使用以下代码替换您的代码。

UserManagerFactory = () => 
{
    var userManager = new ApplicationUserManager(new UserStore<IdentityUser>(new SecurityDbContext()));
    var validator = new UserValidator<IdentityUser>(userManager)
    {
        AllowOnlyAlphanumericUserNames = false
    };
    userManager.UserValidator = validator;

    return userManager;
};

<强>解释

每当您的控制器需要IUserService时，Ninject就会继续，并希望构建一个新的UserService。
如果没有userManager，则无法调用UserService(IUserManager userManager)构造函数，因此Ninject会按照配置调用Startup.UserManagerFactory()。
在您的情况下，UserManagerFactory是一个lambda表达式，它返回捕获的变量userManager。这将始终是相同的实例。
这是第一次按预期工作。处理完请求后，您的用户管理器实例会调用Dispose。
当需要处理下一个请求时，再次使用已经处理的实例。这将失败。
更正的版本也是lambda表达式，但这次我们每次都创建一个新实例。

经过次要代码修改后，“无法访问已处置的对象”

1 个答案: