运行添加迁移时无法加载程序集 Microsoft.EntityFrameworkCore.Design

Question

>我创建了一个具有以下 .csproj 的类库项目：

  <Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netcoreapp1.1</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="1.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="1.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.sqlserver.Design" Version="1.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="1.1.0" />
  </ItemGroup>
</Project>

运行命令时：

Add-Migration -Name Test -Context TestContext

我收到以下错误：

System.IO.FileNotFoundException: Could not load file or assembly 'Microsoft.EntityFrameworkCore.Design, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.
File name: 'Microsoft.EntityFrameworkCore.Design, Culture=neutral, PublicKeyToken=null'
   at System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks, IntPtr ptrLoadContextBinder)
   at System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, RuntimeAssembly reqAssembly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks, IntPtr ptrLoadContextBinder)
   at System.Reflection.Assembly.Load(AssemblyName assemblyRef)
   at Microsoft.EntityFrameworkCore.Tools.ReflectionOperationExecutor..ctor(String assembly, String startupAssembly, String projectDir, String contentRootPath, String dataDirectory, String rootNamespace, String environment)
   at Microsoft.EntityFrameworkCore.Tools.Commands.ProjectCommandBase.CreateExecutor()
   at Microsoft.EntityFrameworkCore.Tools.Commands.MigrationsAddCommand.Execute()
   at Microsoft.DotNet.Cli.CommandLine.CommandLineApplication.Execute(String[] args)
   at Microsoft.EntityFrameworkCore.Tools.Program.Main(String[] args)
Could not load file or assembly 'Microsoft.EntityFrameworkCore.Design, Culture=neutral, PublicKeyToken=null'. The system cannot find the file specified.

但是 Microsoft.EntityFrameworkCore.Design 已安装。

我正在使用Visual Studio Community 2017 (VisualStudio/15.0.0+26228.9(

我错过了什么？

Answer 1

它在添加Microsoft.EntityFrameworkCore.Tools.DotNet并将dotnet工具的版本更改为1.0.0-msbuild2-final后工作，现在我的.csproj是：

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netcoreapp1.1</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="1.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="1.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.sqlserver.Design" Version="1.1.1" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="1.0.0-msbuild2-final" />
    <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools.DotNet" Version="1.0.0-msbuild2-final" />
  </ItemGroup>
</Project>

Answer 2

对我来说，将

启动项目设置为类库后它工作正常，您也可以使用命令无需设置启动项目即可完成

Add-Migration -project [ProjectName] initDB

这也是我的.csproj供参考

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netcoreapp1.1</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="1.1.2" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="1.1.2" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="1.1.1" />
  </ItemGroup>
  <ItemGroup>
    <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore" Version="1.1.2" />  
    <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="1.1.2" />
</ItemGroup>

</Project>

Answer 3

我遵循了Bart Lannoeye的指示：

UWP 应用无法在 AnyCPU 配置中运行我把我的项目定为在 x86 中运行，迁移开始工作。

http://www.bartlannoeye.com/blog/ef-core-migrations-throws-exception-calling-createinstanceandunwrap

Answer 4

我的问题是特定版本的Visual Studio(15.4.5(无法读取IDE设置。 从Ben Day的这个解决方法中，我在命令行上显式设置了安装项目和迁移项目。

这两个命令以这种方式格式化以使其工作。

PM> cd [migrations directory]
PM> Add-Migration -Name [version label] -Context [your context] -s [startup project]