使用 Dapper 升级到 .net core 1.0 后的 MissingMethodException

Question

使用框架 net46 升级到 .NET core 1.0 后，出现以下异常：

System.MissingMethodException was unhandled by user code
HResult=-2146233069
Message=Method not found: 'System.Collections.Generic.IEnumerable`1<!!0> GridReader.Read(Boolean)'.
Source=Sdm.Web
StackTrace:
   at Sdm.Web.SqlAccess.SqlMgr.GetNumbersForMainScreen(TenantId tenantId)
   at Sdm.Web.Test.TestDrivers.SqlMgrTestDriver.TestGetNumbersForMainScreen() in ...\Unittest\SqlMgrTestDriver.cs:line 37
InnerException: (null)

它发生在运行时，就在尝试进入名为 GetNumbersForMainScreen 的方法之前，该方法包含以下代码行：

     using (SqlMapper.GridReader result = connection.QueryMultiple(SqlGetNumbersForMainScreen, new { recent = recent, tid = tenantId.Id }))
        {
            var val = new NumbersForMain()
            {
                AlarmsCriticalCount = result.Read<int>().Single(),
                AlarmsNoncriticalCount = result.Read<int>().Single(),
                RoomsCount = result.Read<int>().Single(),
                UnitsOnlineCount = result.Read<int>().Single(),
                UnitsCount = result.Read<int>().Single(),
            };
            val.UnitsOfflineCount = val.UnitsCount - val.UnitsOnlineCount;

            return val;
        }

这里的变量 connection 是 IDbConnection 类型，QueryMultiple 是 Dapper v1.50.2.0 的扩展方法。

我对此感到很困惑。代码编译得很好，但在运行时我被告知，该方法不存在。

我认为这是与底层依赖项版本不匹配有关的问题。在使用 Maven 或类似工具的 Java 中，我会运行一些依赖关系分析，以查找依赖关系树中的版本控制冲突，但我不知道如何在 .NET 中解决此类问题。

任何有关导致此问题的原因或我如何解决此类问题的建议将不胜感激。

编辑 2016-08-25： 我的 project.json 看起来像这样：

    {
      "userSecretsId": "XXX",
      "buildOptions": {
        "emitEntryPoint": true,
        "preserveCompilationContext": true
      },
      "dependencies": {
        "Dapper": "1.50.2",
        "Dapper-Async": "1.3.0",
        "EntityFramework": "6.1.3",
        "Microsoft.EntityFrameworkCore.SqlServer.Design": "1.0.0",  
        "Microsoft.AspNetCore.Authentication.OpenIdConnect": "1.0.0",
        "Microsoft.AspNetCore.Authentication.Cookies": "1.0.0",
        "Microsoft.AspNetCore.Diagnostics.Elm": "0.1.0",
        "Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore": "1.0.0",
        "Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.0.0",
        "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
        "Microsoft.AspNetCore.Mvc": "1.0.0",
        "Microsoft.AspNetCore.Mvc.TagHelpers": "1.0.0",
        "Microsoft.AspNetCore.Razor.Tools": {
          "version": "1.0.0-preview2-final",
          "type": "build"
        },
        "Microsoft.AspNetCore.StaticFiles": "1.0.0",
        "Microsoft.Extensions.Configuration.FileExtensions": "1.0.0",
        "Microsoft.Extensions.Configuration.Json": "1.0.0",
        "Microsoft.Extensions.Configuration.UserSecrets": "1.0.0",
        "Microsoft.Extensions.Logging": "1.0.0",
        "Microsoft.Extensions.Logging.Console": "1.0.0",
        "Microsoft.Extensions.Logging.Debug": "1.0.0",
        "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0",
        "Microsoft.Extensions.Caching.Abstractions": "1.0.0",
        "Microsoft.Extensions.Caching.Memory": "1.0.0",
        "Newtonsoft.Json": "9.0.1",
        "Microsoft.AspNetCore.Authentication.JwtBearer": "1.0.0",
        "Microsoft.AspNetCore.Authorization": "1.0.0",
        "Microsoft.Azure.Devices": "1.0.5",
        "Microsoft.AspNetCore.HttpOverrides": "1.0.0",
        "EFAttributeConfig": "1.0.0",
        "Twilio": "4.5.0",
        "Sendgrid": "6.3.4",
        "Microsoft.AspNetCore.Routing": "1.0.0",
        "Microsoft.AspNetCore.Hosting": "1.0.0",
        "Microsoft.AspNetCore.Server.Kestrel": "1.0.0",
        "log4net": "2.0.5"
      },
      "tools": {
        "BundlerMinifier.Core": "2.0.238",
        "Microsoft.AspNetCore.Razor.Tools": "1.0.0-preview2-final",
        "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final"
      },

      "frameworks": {
        "net46": { }
      },
      "publishOptions": {
        "include": [
          "wwwroot",
          "Views",
          "appsettings.json",
          "web.config",
          "log4net.xml"
        ], 
        "exclude": [
            "**.user",
            "**.vspscc"
        ]    
      },

      "scripts": {
        "prepublish": [ "bower install", "dotnet bundle" ],
        "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
      }
    }

Answer 1

问题在于您同时引用了Dapper 和Dapper-Async。 Dapper-Async 不是Dapper 的补充，它是一个替换。这意味着两个包都包含Dapper.dll，因此dotnet 对使用哪个包感到困惑，并且由于某种原因，在编译时使用一个，而在运行时使用另一个，导致异常。

解决方案是使用Dapper 或Dapper-Async，但不能同时使用。至于用哪一个，我不知道，因为我不熟悉 Dapper。但是我猜你应该使用Dapper，因为Dapper-Async已经很久没有更新了。