C# 基于ASP.NET Core中的现有数据库创建实体框架模型

我正在尝试基于ASP.NET Core中的现有数据库创建实体框架模型。但是我不能让它工作！我搜索了Stackoverflow和其他网站，查看我的ASP.NET核心Web应用程序项目中的包是否不正确，但我仍然无法使其正常工作。在Package Manager控制台中运行Scaffold DbContext时，我遇到以下错误：

PM> Scaffold-DbContext "Server=.;Database=TravelAgency;Trusted_Connection=True;" Microsoft.EntityFrameworkCore.SqlServer -OutputDir Models
System.AggregateException: Ett eller flera fel har uppst�tt. ---> System.MethodAccessException: Ett f�rs�k av metoden Microsoft.EntityFrameworkCore.Scaffolding.Configuration.Internal.ModelConfiguration.get_EntityConfigurations() 
att komma �t metoden Microsoft.EntityFrameworkCore.Metadata.Internal.EntityTypeNameComparer..ctor() misslyckades.    vid Microsoft.EntityFrameworkCore.Scaffolding.Configuration.Internal.ModelConfiguration.get_EntityConfigurations() 

很抱歉，我没有找到用英语在Package Manager控制台中显示错误的方法。这是关于System.AggregateException：发生了一个或多个错误。 我的project.json文件如下所示：

{
  "buildOptions": {
"emitEntryPoint": true,
"preserveCompilationContext": true
  },
  "dependencies": {
"EntityFramework": "6.1.3",
"Microsoft.AspNetCore.Authentication.Cookies": "1.0.0",
"Microsoft.AspNetCore.Diagnostics": "1.0.0",
"Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore": "1.0.0",
"Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.0.0",
"Microsoft.AspNetCore.Mvc": "1.0.1",
"Microsoft.AspNetCore.Razor.Tools": {
  "type": "build",
  "version": "1.0.0-preview2-final"
},
"Microsoft.AspNetCore.Routing": "1.0.1",
"Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
"Microsoft.AspNetCore.Server.Kestrel": "1.0.1",
"Microsoft.AspNetCore.StaticFiles": "1.0.0",
"Microsoft.EntityFrameworkCore": "1.1.0",
"Microsoft.EntityFrameworkCore.Design": "1.0.0-preview2-final",
"Microsoft.EntityFrameworkCore.SqlServer": "1.1.0",
"Microsoft.EntityFrameworkCore.SqlServer.Design": "1.1.0",
"Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final",
"Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0",
"Microsoft.Extensions.Configuration.Json": "1.0.0",
"Microsoft.Extensions.Configuration.UserSecrets": "1.0.0",
"Microsoft.Extensions.Logging": "1.1.0",
"Microsoft.Extensions.Logging.Console": "1.0.0",
"Microsoft.Extensions.Logging.Debug": "1.0.0",
"Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
"Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0",
"Microsoft.VisualStudio.Web.CodeGeneration.Tools": {
  "version": "1.0.0-preview2-final",
  "type": "build"
},
"Microsoft.VisualStudio.Web.CodeGenerators.Mvc": {
  "type": "build",
  "version": "1.0.0-preview2-final"
},
"NuGet.CommandLine": "3.5.0"
  },
  "frameworks": {

"net461": {}

  },

  "publishOptions": {
"include": [
  "wwwroot",
  "**/*.cshtml",
  "appsettings.json",
  "web.config"
]
  },
  "runtimeOptions": {
"configProperties": {
  "System.GC.Server": true
}
  },
  "scripts": {
"prepublish": [ "bower install", "dotnet bundle" ],
"postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  },
  "tools": {
"BundlerMinifier.Core": "2.0.238",
"Microsoft.AspNetCore.Razor.Tools": "1.0.0-preview2-final",
"Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final",
"Microsoft.Extensions.SecretManager.Tools": "1.0.0-preview2-final",
"Microsoft.VisualStudio.Web.CodeGeneration.Tools": {
  "version": "1.0.0-preview2-final",
  "imports": [
    "portable-net45+win8"
  ]
}
  },
  "userSecretsId": "aspnet-TravelAgencyApplication-3fa3cffa-93a0-470d-b08a-145e604eb5f7"
}

提前谢谢！

---

向您致意，Attila

您应该尝试运行以下命令

Scaffold-DbContext "Server=(localdb)\mssqllocaldb;Database=Blogging;Trusted_Connection=True;" Microsoft.EntityFrameworkCore.SqlServer -OutputDir Models

---

在package manager控制台中使用.net core实现此功能时，我遇到了很多问题。我结束了从命令行发出命令的过程，这使我更加成功。请参见此处，了解如何执行此操作：

例如，从项目目录运行以下命令：

dotnet ef dbcontext scaffold“Server=YourServer；Database=YourDb；integratedsecurity=True；”Microsoft.EntityFrameworkCore.SqlServer--output dir Models

---

这里列出了一个问题，现在已经结束了，但我似乎仍然有问题：

谢谢大家！我不知道我到底做了什么，但我最终成功地使用了Scaffold DbContext命令：

Scaffold-DbContext "Server=DATOR;Database=TravelAgency;Trusted_Connection=True;" Microsoft.EntityFrameworkCore.SqlServer -OutputDir Models

这是destructi6n描述的命令，已根据我的SQL Server 2012数据库进行了调整。现在，我的project.json文件如下所示：

{
  "buildOptions": {
"emitEntryPoint": true,
"preserveCompilationContext": true
  },
  "dependencies": {
"EntityFramework": "6.1.3",
"Microsoft.AspNetCore.Authentication.Cookies": "1.0.0",
"Microsoft.AspNetCore.Diagnostics": "1.0.0",
"Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore": "1.0.0",
"Microsoft.AspNetCore.Identity.EntityFrameworkCore": "1.0.0",
"Microsoft.AspNetCore.Mvc": "1.0.1",
"Microsoft.AspNetCore.Razor.Tools": {
  "type": "build",
  "version": "1.0.0-preview2-final"
},
"Microsoft.AspNetCore.Routing": "1.0.1",
"Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
"Microsoft.AspNetCore.Server.Kestrel": "1.0.1",
"Microsoft.AspNetCore.StaticFiles": "1.0.0",
"Microsoft.EntityFrameworkCore": "1.1.0",
"Microsoft.EntityFrameworkCore.Design": "1.1.0",
"Microsoft.EntityFrameworkCore.SqlServer": "1.1.0",
"Microsoft.EntityFrameworkCore.SqlServer.Design": "1.1.0",
"Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final",
"Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0",
"Microsoft.Extensions.Configuration.Json": "1.0.0",
"Microsoft.Extensions.Configuration.UserSecrets": "1.0.0",
"Microsoft.Extensions.Logging": "1.1.0",
"Microsoft.Extensions.Logging.Console": "1.0.0",
"Microsoft.Extensions.Logging.Debug": "1.0.0",
"Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
"Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0",
"Microsoft.VisualStudio.Web.CodeGeneration.Tools": {
  "version": "1.0.0-preview2-final",
  "type": "build"
},
"Microsoft.VisualStudio.Web.CodeGenerators.Mvc": {
  "type": "build",
  "version": "1.0.0-preview2-final"
},
"NuGet.CommandLine": "3.5.0"
  },
  "frameworks": {

"net461": {}

  },

  "publishOptions": {
"include": [
  "wwwroot",
  "**/*.cshtml",
  "appsettings.json",
  "web.config"
]
  },
  "runtimeOptions": {
"configProperties": {
  "System.GC.Server": true
}
  },
  "scripts": {
"prepublish": [ "bower install", "dotnet bundle" ],
"postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  },
  "tools": {
"BundlerMinifier.Core": "2.0.238",
"Microsoft.AspNetCore.Razor.Tools": "1.0.0-preview2-final",
"Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final",
"Microsoft.Extensions.SecretManager.Tools": "1.0.0-preview2-final",
"Microsoft.VisualStudio.Web.CodeGeneration.Tools": {
  "version": "1.0.0-preview2-final",
  "imports": [
    "portable-net45+win8"
  ]
}
  },
  "userSecretsId": "aspnet-TravelAgencyApplication-3fa3cffa-93a0-470d-b08a-145e604eb5f7"
}

---

你好，阿提拉

谢谢你，但你的意思是我应该创建一个本地数据库，这样才能工作吗？我之前创建了一个Sql Server 2012数据库，尽管我使用了您提到的命令，但我似乎无法使Scaffold DbContext正常工作。您应该做的是将我的连接字符串（即Server=（localdb）\mssqllocaldb；database=Blogging；Trusted_connection=True；）替换为指向您数据库的字符串。我以前在localdb实例中使用过这个命令。如果您将此命令提供给连接字符串，则该命令应适用于您。