Failed to load assembly Microsoft.EntityFrameworkCore.Design when running Add-Migration

Question

I created a class library project with the following .csproj:

<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> 

When executing the command:

 Add-Migration -Name Test -Context TestContext 

I get the following error:

 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. , Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark & stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks, IntPtr ptrLoadContextBinder) 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. 

However, Microsoft.EntityFrameworkCore.Design is already installed.

I am using Visual Studio Community 2017 (VisualStudio / 15.0.0 + 26228.9)

What am I missing?

Answer 1

It worked after adding Microsoft.EntityFrameworkCore.Tools.DotNet and changing the dotnet tools versions to 1.0.0-msbuild2-final, now my .csproj:

 <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

for me, it did a great job after installing the initial project in the class library, and you can do this without installing the launch project using the command

 Add-Migration -project [ProjectName] initDB 

also here is my .csproj for reference

 <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

I followed the directions of Bart Lannoy:

UWP applications cannot work in AnyCPU configuration. I turned on my project to run in x86 and the migrations started working.

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

Answer 4

My problem was in a specific version of Visual Studio (15.4.5) without reading the IDE settings. From this workaround from Ben Day, I explicitly set the installation project and the Migrations project on the command line.

These two teams have been formatted so that they work.

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