dnx。 ef命令返回System.Reflection.ReflectionTypeLoadException

Question

我试图创建我的第一个迁移文件，执行此dnx命令后出现以下错误：

dnx。如果迁移添加了MigrationFile

System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the
 requested types. Retrieve the LoaderExceptions property for more information.
   at System.Reflection.RuntimeModule.GetTypes(RuntimeModule module)
   at System.Reflection.Assembly.GetTypes()
   at Microsoft.Data.Entity.Commands.ContextTool.GetContextTypes(Assembly assembly)
   at Microsoft.Data.Entity.Commands.MigrationTool.GetContextTypes()
   at Microsoft.Data.Entity.Commands.MigrationTool.GetContextType(String name)
   at Microsoft.Data.Entity.Commands.MigrationTool.AddMigration(String migration
Name, String contextTypeName, String startupAssemblyName, String rootNamespace,
String projectDir)
   at Microsoft.Data.Entity.Commands.Program.<>c__DisplayClass12_0.<AddMigration>b__0()
   at Microsoft.Data.Entity.Commands.Program.Execute(String startupProject, Func`1 invoke)
   at Microsoft.Framework.Runtime.Common.CommandLine.CommandLineApplication.Execute(String[] args)
--- End of stack trace from previous location where exception was thrown ---

   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.Framework.Runtime.Common.EntryPointExecutor.Execute(Assembly assembly, String[] args, IServiceProvider serviceProvider)
   at Microsoft.Framework.ApplicationHost.Program.ExecuteMain(DefaultHost host,
String applicationName, String[] args)
   at Microsoft.Framework.ApplicationHost.Program.Main(String[] args)
--- End of stack trace from previous location where exception was thrown ---

   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.Framework.Runtime.Common.EntryPointExecutor.Execute(Assembly assembly, String[] args, IServiceProvider serviceProvider)
   at dnx.host.Bootstrapper.RunAsync(List`1 args, IRuntimeEnvironment env, Frame
workName targetFramework)
   at dnx.host.RuntimeBootstrapper.ExecuteAsync(String[] args, FrameworkName targetFramework)
   at dnx.host.RuntimeBootstrapper.Execute(String[] args, FrameworkName targetFramework)