c# - Entity Framework Core 2.0 Add-Migration 不创建任何迁移文件

Question

最近从 EF Core 1.0 迁移到 EF Core 2.0，并且运行良好。今天我添加了一个新表(代码优先)并将其添加到我的 DbContext 中:

public virtual DbSet<Foo> Foos { get; set; }

当我运行迁移时，我的 DbContext 在一个单独的项目中(记住这一切之前都是有效的)，迁移结束，但没有创建迁移文件。这一切都在 Core 2.0 之前使用:

http://paultechguy.blogspot.com/2017/04/entity-framework-core-migrating-and.html

PM> Add-Migration GradePremade -project Mfc.MfcRepositoryModel -verbose -context MfcDbContext -StartupProject web.xyz
Using project 'class.xyz\Mfc.MfcRepositoryModel'.
Using startup project 'web.xyz'.
Build started...
Build succeeded.
C:\Program Files\dotnet\dotnet.exe exec --depsfile C:\development\xyz\web.xyz\bin\Debug\netcoreapp2.0\web.xyz.deps.json --additionalprobingpath C:\Users\pcarver\.nuget\packages --additionalprobingpath "C:\Program Files\dotnet\sdk\NuGetFallbackFolder" --runtimeconfig C:\development\xyz\web.xyz\bin\Debug\netcoreapp2.0\web.xyz.runtimeconfig.json "C:\Program Files\dotnet\sdk\NuGetFallbackFolder\microsoft.entityframeworkcore.tools\2.0.0\tools\netcoreapp2.0\ef.dll" migrations add GradePremade --json --context MfcDbContext --verbose --no-color --prefix-output --assembly C:\development\xyz\web.xyz\bin\Debug\netcoreapp2.0\Mfc.MfcRepositoryModel.dll --startup-assembly C:\development\xyz\web.xyz\bin\Debug\netcoreapp2.0\web.xyz.dll --project-dir C:\development\xyz\class.xyz\Mfc.MfcRepositoryModel --root-namespace Mfc.MfcRepositoryModel
Using assembly 'Mfc.MfcRepositoryModel'.
Using startup assembly 'web.xyz'.
Using application base 'C:\development\xyz\web.xyz\bin\Debug\netcoreapp2.0'.
Using working directory 'C:\development\xyz\web.xyz'.
Using root namespace 'Mfc.MfcRepositoryModel'.
Using project directory 'C:\development\xyz\class.xyz\Mfc.MfcRepositoryModel'.
Finding DbContext classes...
Finding IDesignTimeDbContextFactory implementations...
Finding application service provider...
Finding BuildWebHost method...
No BuildWebHost method was found on type 'xyz.Program'.
No application service provider was found.
Finding DbContext classes in the project...
Found DbContext 'ApplicationDbContext'.
Found DbContext 'MfcDbContext'.
Using DbContext factory 'MfcContextFactory'.
Using context 'MfcDbContext'.
Finding design-time services for provider 'Microsoft.EntityFrameworkCore.SqlServer'...
Using design-time services from provider 'Microsoft.EntityFrameworkCore.SqlServer'.
Finding IDesignTimeServices implementations in assembly 'web.xyz'...
No design-time services were found.

没有对我来说很明显的错误，也没有创建迁移文件。我已经完成了 Remove-Migration 以开始清理，但仍然没有工作。

Answer 1

.NET Core 类库中存在问题。成功的解决方法是将以下内容放入 Model 项目的 csproj 文件中:

<PropertyGroup>
  <GenerateRuntimeConfigurationFiles>true</GenerateRuntimeConfigurationFiles> 
</PropertyGroup>