實體框架核心2.0添加遷移不會創建任何遷移文件

Question

最近從EF核心1.0遷移到EF核心2.0，它運行良好。今天，我添加了一個新表（代碼優先），並將其與添加到我的DbContext：在一個單獨的項目

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

當我運行遷移，與我的DbContext（記住，這是所有工作之前），遷移結束，但沒有創建遷移文件。這是所有工作之前，核2.0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. 

沒有錯誤，似乎很明顯對我來說，並不會發生遷移的文件。我做了一個移除遷移開始乾淨，但仍然沒有工作。

Answer 1

我不得不標記項目作爲啓動項目。

Answer 2

您將需要更新您的Program類，看起來像這樣

public class Program 
{ 
    public static void Main(string[] args) 
    { 
     var host = BuildWebHost(args); 

     host.Run(); 
    } 

    // Tools will use this to get application services 
    public static IWebHost BuildWebHost(string[] args) => 
     new WebHostBuilder() 
      .UseKestrel() 
      .UseContentRoot(Directory.GetCurrentDirectory()) 
      .UseIISIntegration() 
      .UseStartup<Startup>() 
      .Build(); 
} 

Answer 3

從您的遷移項目的ConfigureServices方法在啓動類中刪除您的所有IDesignTimeDbContextFactory<TContext>實現並註冊DbContext，你會以同樣的方式在運行應用程序時註冊。

然後像往常一樣運行你的migrations命令，這讓我頭疼幾個小時後。在標籤的PropertyGroup

<RuntimeFrameworkVersion>2.0.3</RuntimeFrameworkVersion> 

：

Answer 4

我試圖在.csproj的文件更新運行時版本包括。它爲我工作。

請參見：Russell Seamer's Solution

Answer 5

.NET Core類庫中存在一個問題。成功的解決方法是將在Model項目的csproj文件中的以下內容：

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