Question

我是.net核心的新手，所以问题可能很简单，但我不知道，如何解决它......

尝试在我的代码中使用MySQL数据库，在select上给我一个 MissingMethodException 。

public List<Message> GetMessages(String chatHash, Int32 count = 0)
{
    // exception is generated here 
    return count == 0
       ? Context.Messages()
                    .Where(x => x.Chat.Hash.Equals(chatHash)) // string compaction
                    .Include(x => x.Attachments)
                    .ToList()
        : Context.Messages
                    .Where(x => x.Chat.Hash.Equals(chatHash))
                    .Include(x => x.Attachments)
                    .Take(count)
                    .ToList();
}

示例被简化了一点，没有显示存储库和其他一些包装。

例外情况详见

消息：

Method not found: 'Void Microsoft.EntityFrameworkCore.Query.ExpressionTranslators.Internal.EndsWithTranslator..ctor()'.

堆栈跟踪：

at MySQL.Data.Entity.MySQLCompositeMethodCallTranslator..ctor(ILogger`1 logger)
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass16_0.<RealizeService>b__0(ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
at Microsoft.EntityFrameworkCore.Infrastructure.RelationalServiceCollectionExtensions.<>c.<AddRelational>b__0_4(IServiceProvider p)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass16_0.<RealizeService>b__0(ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServiceCollectionExtensions.<>c.<AddQuery>b__1_8(IServiceProvider p)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass16_0.<RealizeService>b__0(ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServiceCollectionExtensions.<>c.<AddQuery>b__1_4(IServiceProvider p)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass16_0.<RealizeService>b__0(ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServiceCollectionExtensions.<>c.<AddQuery>b__1_2(IServiceProvider p)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass16_0.<RealizeService>b__0(ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServiceCollectionExtensions.<>c.<AddEntityFramework>b__0_10(IServiceProvider p)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass16_0.<RealizeService>b__0(ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetService[T](IServiceProvider provider)
at Microsoft.EntityFrameworkCore.Infrastructure.AccessorExtensions.GetService[TService](IInfrastructure`1 accessor)
at Microsoft.EntityFrameworkCore.DbContext.get_QueryProvider()
at Microsoft.EntityFrameworkCore.Internal.InternalDbSet`1.<.ctor>b__3_0()
at Microsoft.EntityFrameworkCore.Internal.LazyRef`1.get_Value()
at Microsoft.EntityFrameworkCore.Internal.InternalDbSet`1.System.Linq.IQueryable.get_Provider()
at System.Linq.Queryable.Where[TSource](IQueryable`1 source, Expression`1 predicate)
at DesignService.Service.Concrete.ChatService.GetMessages(String chatHash, Int32 count) in D:\DesignService\src\DesignService\Service\Concrete\ChatService.cs:line 23

我的 project.json 看起来像这样

{
  "title": "DesingService",
  "version": "1.0.0-*",
  "runtimes": {
    "win81-x64": {},
    "win10-x64": {},
    "ubuntu.16.04-x64": {}
  },
  "buildOptions": {
    "emitEntryPoint": true,
    "optimize": true,
    "debugType": "portable",
    "define": ["USE_MySQL"],
    "copyToOutput": { "includeFiles": ["Settings.json"] }
  },

  "dependencies": {
    "MailKit": "1.10.0",
    "Microsoft.AspNetCore.Hosting": "1.1.0-preview1-final",
    "Microsoft.AspNetCore.Http.Abstractions": "1.1.0-preview1-final",
    "Microsoft.AspNetCore.Server.Kestrel": "1.1.0-preview1-final",
    "Microsoft.EntityFrameworkCore": "1.1.0-preview1-final",
    "Microsoft.EntityFrameworkCore.Design": "1.1.0-preview1-final",
    "Microsoft.EntityFrameworkCore.SqlServer": "1.1.0-preview1-final",
    "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview3-final",
    "Microsoft.NETCore.App": "1.1.0-preview1-001100-00",
    "Newtonsoft.Json": "9.0.2-beta1",
    "SapientGuardian.EntityFrameworkCore.MySql": "7.1.10"
  },
  "tools": {
    "Microsoft.EntityFrameworkCore.Tools.DotNet": "1.0.0-preview3-final"
  },

  "frameworks": {
    "netcoreapp1.0": {
      "imports": "dnxcore50"
    }
  }
}

虽然，我尝试使用官方提供商 MySql.Data.EntityFrameworkCore ，这会产生相同的结果。

代码已经过MS SQL服务器测试，运行正常。

也许你可以提出一些建议或建议？

提前致谢，尼克。

Answer 1

问题与sql provider有关。在当前版本中已经修复。

使用.net核心应用程序的MySQL提供程序生成MissingMethodException

1 个答案: