开发应用程序并使用两台不同的计算机。据我所知，他们都在Windows 10（1803）的同一版本。就在最近，我开始在一台机器上遇到问题。该应用程序使用个人帐户身份验证，并在登录提示符，一旦用户输入他们的用户名和密码并单击登录，它将引发以下错误：
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>>)'.
它确定为问题的代码是（在第88行）：
Line 86: // To enable password failures to trigger account lockout, change to shouldLockout: true
Line 87: //var result = await SignInManager.PasswordSignInAsync(model.Email, model.Password, model.RememberMe, shouldLockout: false);
Line 88: var result = await SignInManager.PasswordSignInAsync(model.UserName, model.Password, model.RememberMe, shouldLockout: false);
Line 89: switch (result)
Line 90: {
我已经从可疑机器中完全删除了Project并从Git重新克隆，但同样的问题。我通过我的参考资料进行了比较，并与它正在进行的机器进行了比较，并且它们都匹配。
仅供参考，这是堆栈跟踪：
[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__6c.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) +537
Microsoft.AspNet.Identity.UserManager`2.FindByNameAsync(String userName) +56
Microsoft.AspNet.Identity.Owin.<PasswordSignInAsync>d__29.MoveNext() +104
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() +24
CaseNotesPlus.Controllers.<Login>d__12.MoveNext() in D:\Projects\CaseNotesPlus\CaseNotesPlus\Controllers\AccountController.cs:88
System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +99
System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +58
System.Web.Mvc.Async.TaskAsyncActionDescriptor.EndExecute(IAsyncResult asyncResult) +97
System.Web.Mvc.Async.<>c__DisplayClass8_0.<BeginInvokeAsynchronousActionMethod>b__1(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__11_0() +50
System.Web.Mvc.Async.<>c__DisplayClass11_1.<InvokeActionMethodFilterAsynchronouslyRecursive>b__2() +228
System.Web.Mvc.Async.<>c__DisplayClass7_0.<BeginInvokeActionMethodWithFilters>b__1(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__DisplayClass3_6.<BeginInvokeAction>b__3() +35
System.Web.Mvc.Async.<>c__DisplayClass3_1.<BeginInvokeAction>b__5(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.<>c.<BeginExecuteCore>b__152_1(IAsyncResult asyncResult, ExecuteCoreState innerState) +11
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) +45
System.Web.Mvc.<>c.<BeginExecute>b__151_2(IAsyncResult asyncResult, Controller controller) +13
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.<>c.<BeginProcessRequest>b__20_1(IAsyncResult asyncResult, ProcessRequestState innerState) +28
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() +9874329
System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +48
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +159
我已经验证我在两台计算机上都有相同的.NET Framework安装程序：版本信息：Microsoft .NET Framework版本：4.0.30319; ASP.NET版本：4.7.3056.0
该项目的目标是4.6.1
感谢您提供任何帮助或建议。
答案 0 :(得分：0)
查看CaseNotesPlus \ Controllers \ AccountController.cs中的PasswordSignInAsync方法，可能在方法上方有一个action属性。也许它有某种机器名称规范检查。
答案 1 :(得分：0)
检查您的参考文献并确保您没有引用“gac”中的任何内容。这可以解释为什么它在一台机器上工作而在另一台机器上工作。
在我看来，您的问题与您的ef版本有关（身份需要的版本与游览代码所引用的版本不同）。检查你的装配绑定。
答案 2 :(得分：0)
确保您使用的是 Entity Framework版本6.2
我遇到了同样的问题，因为我使用的是Linq方法FirstOrDefaultAsync()和EntityFramework 6.1.3 （在6.2.0之前）
根据Microsoft关于“ QueryableExtensions.FirstOrDefaultAsync（）”的文档： https://docs.microsoft.com/en-us/dotnet/api/system.data.entity.queryableextensions.firstordefaultasync?view=entity-framework-6.2.0
此方法仅适用于** EntityFramework 6.2版本**
适用于
实体框架
6.2.0