EF Core 数据库第一种方法：Scaffold-DbContext 不被识别为 cmdlet 的名称

Question

我正在使用 EF Core，并且正在尝试从数据库生成模型。 我创建了一个单独的 ASP.NET Core Web 应用程序，因为从类库生成它对我不起作用。

我已经多次成功地从数据库中生成了实体类，但突然停止工作。 这真的很奇怪，因为我这不是第一次，而且我没有改变任何东西，是什么导致它停止工作？

这是project.json：

  {
  "dependencies": {
    "Microsoft.EntityFrameworkCore.SqlServer": "1.1.0",
    "Microsoft.EntityFrameworkCore.Tools": "1.1.0-preview4-final",
    "Microsoft.AspNetCore.Mvc": "1.1.0",
    "Microsoft.AspNetCore.Routing": "1.1.0",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.1.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.1.0",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.1.0",
    "Microsoft.Extensions.Configuration.FileExtensions": "1.1.0",
    "Microsoft.Extensions.Configuration.Json": "1.1.0",
    "Microsoft.Extensions.Logging": "1.1.0",
    "Microsoft.Extensions.Logging.Console": "1.1.0",
    "Microsoft.Extensions.Logging.Debug": "1.1.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.1.0",
    "Microsoft.NETCore.App": {
      "version": "1.1.0",
      "type": "platform"
    },
    "Microsoft.EntityFrameworkCore.SqlServer.Design": "1.1.0"
  },

  "tools": {

    "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final",
    "Microsoft.AspNetCore.Server.IISIntegration.Tools": "1.0.0-preview2-final"
  },

  "frameworks": {
    "netcoreapp1.0": {
      "imports": [
        "dotnet5.6",
        "portable-net45+win8"
      ]
    }
  },

  "buildOptions": {
    "emitEntryPoint": true,
    "preserveCompilationContext": true
  },

  "runtimeOptions": {
    "configProperties": {
      "System.GC.Server": true
    }
  }
}

这是命令：

 Scaffold-DbContext "Server= myserver;Database=db;User Id=sa;Password=pass;" Microsoft.EntityFrameworkCore.SqlServer -OutputDir EntityModels 

错误：

 Scaffold-DbContext : The term 'Scaffold-DbContext' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the 
name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ Scaffold-DbContext "Server=myserver;Database=db...
+ ~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (Scaffold-DbContext:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

我重新启动了visual studio，问题仍然存在。

Answer 1

dependencies的版本与tools不同：

从dependencies ：

"Microsoft.EntityFrameworkCore.Tools": "1.1.0-preview4-final",

从tools ：

"Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final",