Question

我在ASP.NET Core 2.0 Preview上使用Pomelo 1.1.2以及EF 2.0 Preview。使用他们的演示代码，每次调用＆＃34; UseMySql＆＃34;我都会得到以下异常：

System.TypeLoadException occurred
  HResult=0x80131522
  Message=Method 'Clone' in type 'Microsoft.EntityFrameworkCore.Internal.MySqlOptionsExtension' from assembly 'Pomelo.EntityFrameworkCore.MySql, Version=1.1.1.0, Culture=neutral, PublicKeyToken=null' does not have an implementation.
  Source=<Cannot evaluate the exception source>
  StackTrace:
   at Microsoft.EntityFrameworkCore.MySqlDbContextOptionsExtensions.UseMySql(DbContextOptionsBuilder optionsBuilder, String connectionString, Action`1 mySqlOptionsAction)
   at CoreTest1.Startup.<ConfigureServices>b__4_0(DbContextOptionsBuilder options) in C:\DEV\Experiments\CoreTest1\CoreTest1\Startup.cs:line 27
   at Microsoft.Extensions.DependencyInjection.EntityFrameworkServiceCollectionExtensions.<>c__DisplayClass0_0`1.<AddDbContext>b__0(IServiceProvider p, DbContextOptionsBuilder b)
   at Microsoft.Extensions.DependencyInjection.EntityFrameworkServiceCollectionExtensions.DbContextOptionsFactory[TContext](IServiceProvider applicationServiceProvider, Action`2 optionsAction)
   at Microsoft.Extensions.DependencyInjection.EntityFrameworkServiceCollectionExtensions.<>c__DisplayClass5_0`1.<AddCoreServices>b__0(IServiceProvider p)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactoryService(FactoryService factoryService, ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(IServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitSingleton(SingletonCallSite singletonCallSite, ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(IServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(IServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(IServiceCallSite callSite, TArgument argument)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass17_0.<RealizeService>b__0(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetService[T](IServiceProvider provider)
   at CoreTest1.Controllers.HomeController.Index() in C:\DEV\Experiments\CoreTest1\CoreTest1\Controllers\HomeController.cs:line 18
   at Microsoft.AspNetCore.Mvc.Internal.ObjectMethodExecutor.Execute(Object target, Object[] parameters)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.<InvokeActionMethodAsync>d__18.MoveNext()

想知道这是否仅仅是因为2.0预览库？有任何想法吗？我试着在Git上查看他们的源代码，看看我是否能发现任何错误，但不能。

Answer 1

让我们看看EF Core 2.0 Preview 1 announcement：

如果您使用的是第三方数据库提供程序，请检查是否已发布依赖于2.0.0-preview1-final的更新。如果有，那么只需升级到新版本。如果没有，那么你将无法升级，因为版本2.0包含几个重大更改，并且1. *提供商不会使用它。

这意味着，在可比较的release之前，预计Pomelo不会支持EF Core 2.0。被生产。

Answer 2

最近，在我的项目更新到.NET Core 2.0期间遇到了同样的错误。此时，https://github.com/PomeloFoundation/Pomelo.EntityFrameworkCore.MySql中描述了解决方案基本上，将软件包更新到预先发布的版本 2.0.0-rc - *

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Answer 3

如果您使用的是asp.net core 2.0，则需要使用pomelo 2.0.0。 Asp.net core 2.0不适用于pomelo 2.1或更高版本。

使用Pomelo MySQL EF提供程序与ASP.NET Core 2.0 Preview的错误

3 个答案: