从 EDMX 切换到 Code First 后的迁移抛出 MetadataException

Question

我正在将项目从使用 EDMX 文件更改为 Code First。该项目是解决方案中的几个项目之一，它只包含实体和 DbContext class.

这是我目前所做的：

从解决方案中删除了旧项目（但还没有删除它，只是重命名了文件夹）。
向解决方案中添加了一个新的 class 库项目，并为其指定了与旧项目相同的名称。
使用 NuGet 添加 Entity Framework 到新项目。
将旧 EDMX 文件生成的所有实体 classes 复制到新项目并全部包含它们。
也复制了 DbContext class。
修改了 app.config 文件以将连接字符串更改为没有元数据内容的标准连接字符串。
添加了对用于使用旧项目的所有其他项目的引用。

一切看起来都很好并且编译没有错误，但是当我尝试 enable-migrations 它抛出这个错误：

PM> enable-migrations
Checking if the context targets an existing database...
System.Data.Entity.Core.MetadataException: Unable to load the specified metadata resource.
   at System.Data.Entity.Core.Metadata.Edm.MetadataArtifactLoaderCompositeResource.LoadResources(String assemblyName, String resourceName, ICollection`1 uriRegistry, MetadataArtifactAssemblyResolver resolver)
   at System.Data.Entity.Core.Metadata.Edm.MetadataArtifactLoaderCompositeResource.CreateResourceLoader(String path, ExtensionCheck extensionCheck, String validExtension, ICollection`1 uriRegistry, MetadataArtifactAssemblyResolver resolver)
   at System.Data.Entity.Core.Metadata.Edm.MetadataArtifactLoader.Create(String path, ExtensionCheck extensionCheck, String validExtension, ICollection`1 uriRegistry, MetadataArtifactAssemblyResolver resolver)
   at System.Data.Entity.Core.Metadata.Edm.MetadataCache.SplitPaths(String paths)
   at System.Data.Entity.Core.Common.Utils.Memoizer`2.<>c__DisplayClass2.<Evaluate>b__0()
   at System.Data.Entity.Core.Common.Utils.Memoizer`2.Result.GetValue()
   at System.Data.Entity.Core.Common.Utils.Memoizer`2.Evaluate(TArg arg)
   at System.Data.Entity.Core.Metadata.Edm.MetadataCache.GetArtifactLoader(DbConnectionOptions effectiveConnectionOptions)
   at System.Data.Entity.Core.Metadata.Edm.MetadataCache.GetMetadataWorkspace(DbConnectionOptions effectiveConnectionOptions)
   at System.Data.Entity.Core.EntityClient.EntityConnection.GetMetadataWorkspace()
   at System.Data.Entity.Core.Objects.ObjectContext.RetrieveMetadataWorkspaceFromConnection()
   at System.Data.Entity.Core.Objects.ObjectContext..ctor(EntityConnection connection, Boolean isConnectionConstructor, ObjectQueryExecutionPlanFactory objectQueryExecutionPlanFactory, Translator translator, ColumnMapFactory columnMapFactory)
   at System.Data.Entity.Internal.InternalConnection.CreateObjectContextFromConnectionModel()
   at System.Data.Entity.Internal.LazyInternalConnection.CreateObjectContextFromConnectionModel()
   at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
   at System.Data.Entity.Internal.LazyInternalContext.get_ModelBeingInitialized()
   at System.Data.Entity.Infrastructure.EdmxWriter.WriteEdmx(DbContext context, XmlWriter writer)
   at System.Data.Entity.Utilities.DbContextExtensions.<>c__DisplayClass1.<GetModel>b__0(XmlWriter w)
   at System.Data.Entity.Utilities.DbContextExtensions.GetModel(Action`1 writeXml)
   at System.Data.Entity.Utilities.DbContextExtensions.GetModel(DbContext context)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration, DbContext usersContext, DatabaseExistenceState existenceState, Boolean calledByCreateDatabase)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration)
   at System.Data.Entity.Migrations.Design.MigrationScaffolder..ctor(DbMigrationsConfiguration migrationsConfiguration)
   at System.Data.Entity.Migrations.Design.ToolingFacade.ScaffoldRunner.Run()
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.AppDomain.DoCallBack(CrossAppDomainDelegate callBackDelegate)
   at System.Data.Entity.Migrations.Design.ToolingFacade.Run(BaseRunner runner)
   at System.Data.Entity.Migrations.Design.ToolingFacade.ScaffoldInitialCreate(String language, String rootNamespace)
   at System.Data.Entity.Migrations.EnableMigrationsCommand.<>c__DisplayClass2.<.ctor>b__0()
   at System.Data.Entity.Migrations.MigrationsDomainCommand.Execute(Action command)
Unable to load the specified metadata resource.

看起来它仍然认为我在使用 EDMX。当我尝试运行应用程序时，我也遇到了这个错误。

我错过了什么？

Answer 1

您必须更改起始项目（asp.net 或 winforms 项目）的连接字符串。

从 EDMX 切换到 Code First 后的迁移抛出 MetadataException

Migrations after switching from EDMX to Code First throws MetadataException

entity-framework

edmx

ef-code-first

entity-framework-migrations