C# ASP NET MVC-无法注册和登录

我已经创建了一个新的ASP NET应用程序。尝试注册时，出现以下错误-找不到方法：

 'System.Threading.Tasks.Task`1<!!0>
 System.Data.Entity.QueryableExtensions.FirstOrDefaultAsync(System.Linq.IQueryable`1<!!0>,
 System.Linq.Expressions.Expression`1<System.Func`2<!!0,Boolean>>)'.

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问题似乎出现在第155行。在我同事的电脑上，同样的项目运行得非常好。关于如何修复它，有什么想法吗？

我见过这种问题偶尔出现在包含多个项目的解决方案中，这些项目引用了程序集的不同版本，其中一个版本有方法，而另一个版本没有。编译项目时，缺少方法的程序集被复制到bin文件夹中，导致代码在运行时无法找到该方法，从而导致此异常

在这种情况下，听起来您可能会遇到类似的情况，我建议您执行以下步骤，看看是否有帮助：

关闭Visual Studio 删除解决方案中所有项目的所有bin和obj文件夹 删除包含已下载nuget软件包的软件包文件夹 重新打开解决方案 确保所有项目都设置为相同的.NET版本，并使用相同的包版本，特别是此问题出现的实体框架 重建解决方案

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这里的目标是清除旧版本中可能遗留的任何内容，或者如果某个内容被重命名，等等，并使所有内容恢复到新状态。

这不是一条完整的异常消息。你也可以发布异常消息文本吗？我们还可能需要在UserManager中查看一些代码。就你的问题而言，我们没有足够的信息来回答你的问题。我想这是MissingMethodException？如果是这样，FirstOrDefault仅在NET4.5实体框架程序集中可用，因此您需要更新到该程序集。我发布了完整的异常消息这是否回答了您的问题？Linq方法仅在EntityFramework 6.2版本中可用。请确保您使用的是实体框架版本6.2。不幸的是，问题仍然存在

 System.MissingMethodException: Method not found: 'System.Threading.Tasks.Task`1<!!0> System.Data.Entity.QueryableExtensions.FirstOrDefaultAsync(System.Linq.IQueryable`1<!!0>, System.Linq.Expressions.Expression`1<System.Func`2<!!0,Boolean>>)'.

[MissingMethodException: Method not found: 'System.Threading.Tasks.Task`1<!!0> System.Data.Entity.QueryableExtensions.FirstOrDefaultAsync(System.Linq.IQueryable`1<!!0>, System.Linq.Expressions.Expression`1<System.Func`2<!!0,Boolean>>)'.]
   Microsoft.AspNet.Identity.EntityFramework.<GetUserAggregateAsync>d__67.MoveNext() +0
   System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1.Start(TStateMachine& stateMachine) +94
   Microsoft.AspNet.Identity.EntityFramework.UserStore`6.GetUserAggregateAsync(Expression`1 filter) +146
   Microsoft.AspNet.Identity.EntityFramework.UserStore`6.FindByNameAsync(String userName) +525
   Microsoft.AspNet.Identity.UserManager`2.FindByNameAsync(String userName) +56
   Microsoft.AspNet.Identity.<ValidateUserName>d__14.MoveNext() +380
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +102
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +64
   Microsoft.AspNet.Identity.<ValidateAsync>d__13.MoveNext() +262
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +102
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +64
   Microsoft.AspNet.Identity.<CreateAsync>d__73.MoveNext() +517
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +102
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +64
   Microsoft.AspNet.Identity.<CreateAsync>d__79.MoveNext() +442
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +102
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +64
   System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() +29
   Project.Controllers.<Register>d__15.MoveNext() in C:\Users\Mateusz\Documents\Visual Studio 2015\Projects\testt\test3\Project\Project\Controllers\AccountController.cs:155
   System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +102
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +64
   System.Web.Mvc.Async.TaskAsyncActionDescriptor.EndExecute(IAsyncResult asyncResult) +97
   System.Web.Mvc.Async.<>c__DisplayClass37.<BeginInvokeAsynchronousActionMethod>b__36(IAsyncResult asyncResult) +17
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +32
   System.Web.Mvc.Async.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d() +50
   System.Web.Mvc.Async.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() +228
   System.Web.Mvc.Async.<>c__DisplayClass33.<BeginInvokeActionMethodWithFilters>b__32(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +34
   System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +26
   System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +100
   System.Web.Mvc.Async.WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27
   System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +13
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +36
   System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller) +12
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +22
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
   System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +21
   System.Web.Mvc.Async.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult) +29
   System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +576
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +132
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +163

Row 153:            {
Row 154:                var user = new ApplicationUser { UserName = model.Email, Email = model.Email };
Row 155:                var result = await UserManager.CreateAsync(user, model.Password);
Row 156:                if (result.Succeeded)
Row 157:                {