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我的模型文件夹中有两个简单的 poco 类，我想使用实体框架来创建迁移。我还有一个 dbcontext 类，这是我想用作迁移的实例。

当我尝试运行时： dnx ef migrations add IntialCommit

我收到以下错误无法从程序集“Microsoft.Framework.Configuration，Version=1.0.0.0，Culture=neutral，PublicKeyToken=null”加载类型“Microsoft.Framework.Configuration.Helper.ConfigurationHelper”。

即使我有正确的包，（Microsoft.Framework.Configuration）

知道为什么我会收到此错误吗？

AnimalsContext.cs

public class Animalscontext :DbContext
{
    public DbSet<Animalscontext> animals  { get; set; }
    public DbSet<Dog> dog { get; set; }

}

动物.cs

     public class Animals
        {

            public int ID { get; set; }
            public string Name { get; set; }

            public List<Dog> dogs { get; set; }
}

狗.cs

 public class Dog
{

    public int ID { get; set; }

    public string breed { get; set; }
}

项目.json

  "dependencies": {
    "EntityFramework.Commands": "7.0.0-*",
    "EntityFramework.SqlServer": "7.0.0-*",
    "Microsoft.AspNet.Diagnostics": "1.0.0-*",
    "Microsoft.AspNet.Diagnostics.Entity": "7.0.0-*",
    "Microsoft.AspNet.Mvc": "6.0.0-*",
    "Microsoft.AspNet.Mvc.TagHelpers": "6.0.0-*",
    "Microsoft.AspNet.Server.IIS": "1.0.0-*",
    "Microsoft.AspNet.Server.WebListener": "1.0.0-*",
    "Microsoft.AspNet.StaticFiles": "1.0.0-*",
    "Microsoft.AspNet.Tooling.Razor": "1.0.0-*",
    "Microsoft.Framework.Configuration": "1.0.0-*",
    "Microsoft.Framework.Configuration.CommandLine": "1.0.0-*",
    "Microsoft.Framework.Configuration.Json": "1.0.0-*",
    "Microsoft.Framework.Logging": "1.0.0-*",
    "Microsoft.Framework.Logging.Console": "1.0.0-*",
    "Microsoft.Framework.Logging.Debug": "1.0.0-*",
    "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0-*"
  },

  "commands": {
    "web": "Microsoft.AspNet.Hosting --config hosting.ini",
    "ef": "EntityFramework.Commands"
  }

启动.cs

services.AddEntityFramework()
                .AddSqlServer()
                .AddDbContext<Animalscontext>(DbContextOptionsBuilder => DbContextOptionsBuilder.UseSqlServer(connectionString));

输出

Using context 'Animalscontext'.
System.TypeLoadException: Could not load type 'Microsoft.Framework.Configuration.Helper.ConfigurationHelper' from assembly 'Microsoft.Framework.Configuration, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.
   at Microsoft.Framework.Configuration.JsonConfigurationExtensions.AddJsonFile(IConfigurationBuilder configuration, String path, Boolean optional)
   at WebApplication2.Startup..ctor(IHostingEnvironment env, IApplicationEnvironment appEnv) in C:\Users\JConterio\Documents\Visual Studio 2015\Projects\WebApplication2\src\WebApplication2\Startup.cs:line 21
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.Framework.DependencyInjection.ActivatorUtilities.ConstructorMatcher.CreateInstance(IServiceProvider provider)
   at Microsoft.Framework.DependencyInjection.ActivatorUtilities.GetServiceOrCreateInstance(IServiceProvider provider, Type type)
   at Microsoft.AspNet.Hosting.Startup.StartupLoader.LoadMethods(Type startupType, IList`1 diagnosticMessages)
   at Microsoft.AspNet.Hosting.Internal.HostingEngine.EnsureStartup()
   at Microsoft.AspNet.Hosting.Internal.HostingEngine.EnsureApplicationServices()
   at Microsoft.AspNet.Hosting.Internal.HostingEngine.get_ApplicationServices()
   at Microsoft.Data.Entity.Design.DbContextOperations.TryCreateContextFromStartup(Type type)
   at Microsoft.Data.Entity.Design.DbContextOperations.CreateContext(String contextType)
   at Microsoft.Data.Entity.Design.MigrationsOperations.AddMigration(String name, String contextType)
   at Microsoft.Data.Entity.Commands.Program.AddMigration(String name, String context)
   at Microsoft.Data.Entity.Commands.Program.<>c__DisplayClass7_6.<Main>b__15()
   at Microsoft.Dnx.Runtime.Common.CommandLine.CommandLineApplication.Execute(String[] args)
   at Microsoft.Data.Entity.Commands.Program.Main(String[] args)
Could not load type 'Microsoft.Framework.Configuration.Helper.ConfigurationHelper' from assembly 'Microsoft.Framework.Configuration, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'.
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1 回答 1

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尽量避免使用1.0.0-*，除非您打算测试夜间构建。

尝试使用1.0.0-beta8已发布和测试的特定软件包。为确保您使用的是最新的软件包，请更改您的参考并重试。如果您有 VS2015，请确保也将您的工具更新到 Beta8。

这应该可以解决您的大部分问题。否则，请尝试使用最新 Beta 版的“文件 > 新项目”并比较您的project.json文件。

于 2015-11-10T19:18:45.970 回答