ASP.NET 5 EntityFramework.Core 7.0.0-rc1-final 问题 - 编译器希望引用未找到的 7.0.0.0

Question

我也有同样的问题。我在project.json 文件中添加了以下依赖项：

"dependencies": {
    "EntityFramework": "7.0.0-beta4",
    "EntityFramework.Core": "7.0.0-rc1-final",
    "EntityFramework.SqlServer": "7.0.0-beta8",
    "EntityFramework.Commands": "7.0.0-rc1-final"
  },
  "commands": {
    "web": "Microsoft.AspNet.Server.Kestrel",
    "ef": "EntityFramework.Commands"
  },
...

我使用dnu install EntityFramework 和dnu install EntityFramework.SqlServer 来安装软件包。 "EntityFramework": "7.0.0-beta4", 由安装程序自己自动写入dependencies 节点下。

问题/问题 1：令我惊讶的是，当我为 EntityFramework 提取智能时，我展示的可用版本只有 6.1.3！

问题 2：当我使用 dnu build 编译我的应用程序时（我在 dependencies 节点下手动添加 EntityFramework 程序集（.Core 和 .Commands）后运行了 dnu restore 命令，我得到了一堆编译错误：

The type 'DbContextOptionsBuilder' is defined in an assembly that is not referenced. You must add a reference to assembly 'EntityFramework.Core, Version=7.0.0.0, Culture=neutral, PublicKeyToken=null'.
D:\Projects\aspnet\apiservice\Models\SampleData.cs(12,41): DNXCore,Version=v5.0 error CS0308: The non-generic method 'IServiceProvider.GetService(Type)' cannot be used with type arguments
D:\Projects\aspnet\apiservice\Models\SampleData.cs(13,32): DNXCore,Version=v5.0 error CS0308: The non-generic method 'IServiceProvider.GetService(Type)' cannot be used with type arguments
D:\Projects\aspnet\apiservice\Models\SampleData.cs(14,29): DNXCore,Version=v5.0 error CS1061: 'object' does not contain a definition for 'Books' and no extension method 'Books' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)
D:\Projects\aspnet\apiservice\Models\SampleData.cs(15,42): DNXCore,Version=v5.0 error CS1061: 'object' does not contain a definition for 'Authors' and no extension method 'Authors' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)
D:\Projects\aspnet\apiservice\Models\SampleData.cs(17,43): DNXCore,Version=v5.0 error CS1061: 'object' does not contain a definition for 'Authors' and no extension method 'Authors' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)
D:\Projects\aspnet\apiservice\Models\SampleData.cs(19,45): DNXCore,Version=v5.0 error CS1061: 'object' does not contain a definition for 'Authors' and no extension method 'Authors' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)
D:\Projects\aspnet\apiservice\Models\SampleData.cs(22,29): DNXCore,Version=v5.0 error CS1061: 'object' does not contain a definition for 'Books' and no extension method 'Books' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)
D:\Projects\aspnet\apiservice\Models\SampleData.cs(61,29): DNXCore,Version=v5.0 error CS1061: 'object' does not contain a definition for 'SaveChanges' and no extension method 'SaveChanges' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)

如果我删除 .Core 和 .Commands 程序集引用项目构建正常。

然后我将EntityFramework.Core 的版本更改为7.0.0.0，如错误中所述：

The type 'DbContextOptionsBuilder' is defined in an assembly that is not referenced. You must add a reference to assembly 'EntityFramework.Core, Version=7.0.0.0, Culture=neutral, PublicKeyToken=null'.

但是dnu restore 现在给了我以下信息：

Unable to locate Dependency EntityFramework.Core >= 7.0.0
Writing lock file D:\Projects\aspnet\apiservice\project.lock.json
Restore complete, 6675ms elapsed

Errors in D:\Projects\aspnet\apiservice\project.json
    Unable to locate Dependency EntityFramework.Core >= 7.0.0

我是asp.net 5Visual Studio code平台的新手。而且我不能使用Visual Studio 2015，因为开发团队的其他成员正在使用 OSX。

这对我来说是一个学习项目。要求很简单。连接 SQL Server 数据库，使用 Entity Framework 拉取master-child 关系数据。

搞砸了！救命！！

提前致谢

更新

1. 我可以看到project.json 中所有版本为7.0.0-rc1-final 的软件包的主要变化。我使用 Yeoman 生成器工具创建项目，但看起来您通过 Visual Studio 更正了包。那么，我是否必须手动更新软件包版本并restore 他们？

2. Yeoman 创建/生成项目时，默认没有添加global.json 文件。我可以手动添加它并手动将代码放入其中吗？这行得通吗？

3. 我还可以看到在 project.json 文件中添加了一些额外的包引用，这些引用是 Yeoman 生成器默认未添加的 - 例如 Microsoft.AspNet.Tooling.Razor、Microsoft.Extensions.Logging.Console、Microsoft.Extensions.Logging.Debug、Microsoft.Extensions.Logging 等。它们都在项目中得到有效使用吗？因为生成器没有自动添加它们，我可以手动添加它们并使用dnu restore 恢复吗？如果我手动添加，这会对项目有什么影响吗？

Answer 1

您应该从依赖项中删除 "EntityFramework"（删除"EntityFramework": "7.0.0-beta4" 行）并使用

"EntityFramework.MicrosoftSqlServer": "7.0.0-rc1-final",
"EntityFramework.MicrosoftSqlServer.Design": "7.0.0-rc1-final",
"EntityFramework.Commands": "7.0.0-rc1-final"

仅限。如果您添加了"EntityFramework.MicrosoftSqlServer": "7.0.0-rc1-final"，则不需要显式添加"EntityFramework.Core": "7.0.0-rc1-final"，因为存在以下依赖关系：

"EntityFramework.MicrosoftSqlServer": "7.0.0-rc1-final":
    "EntityFramework.Relational": "7.0.0-rc1-final":
        "EntityFramework.Core": "7.0.0-rc1-final"

我的意思是EntityFramework.MicrosoftSqlServer 需要EntityFramework.Relational，这需要EntityFramework.Core。

您应该另外验证global.json 是否包含"sdk": { "version": "1.0.0-rc1-update1" }。

已更新：我检查了您上传的测试项目。它有很多小问题。我修改了它。您可以下载修改后的项目here。 不要忘记修复appsettings.json中使用的ConnectionString，它包含我在我使用的Server。

最重要的变化是使用更简单的BookContext.cs：

using Microsoft.Data.Entity;

namespace apiservice.Models {
    public class BookContext : DbContext {
        public DbSet<Author> Authors { get; set; }
        public DbSet<Book> Books { get; set; }
    }
}

下面SampleData.cs的用法

using System;
using System.Linq;
using Microsoft.Data.Entity;
using Microsoft.Extensions.DependencyInjection;

namespace apiservice.Models
{
    public static class SampleData
    {
        public static void Initialize(IServiceProvider serviceProvider) {
            var context=serviceProvider.GetService<BookContext>();
            context.Database.Migrate();
            if (!context.Books.Any()) {
                var austen = context.Authors.Add(
                    new Author { LastName = "Austen", FirstName = "Jane" }).Entity;
                var dickens = context.Authors.Add(
                    new Author { LastName = "Dickens", FirstName = "Charles" }).Entity;
                var cervantes = context.Authors.Add(
                    new Author { LastName = "Cervantes", FirstName = "Miguel" }).Entity;

                context.Books.AddRange(
                    new Book {
                        Title = "Pride and Prejudice",
                        Year = 1813,
                        Author = austen,
                        Price = 9.99M,
                        Genre = "Comedy of manners"
                    },
                    new Book {
                        Title = "Northanger Abbey",
                        Year = 1817,
                        Author = austen,
                        Price = 12.95M,
                        Genre = "Gothic parody"
                    },
                    new Book {
                        Title = "David Copperfield",
                        Year = 1850,
                        Author = dickens,
                        Price = 15,
                        Genre = "Bildungsroman"
                    },
                    new Book {
                        Title = "Don Quixote",
                        Year = 1617,
                        Author = cervantes,
                        Price = 8.95M,
                        Genre = "Picaresque"
                    }
                );

                context.SaveChanges(); 
            }
        }
    }    
}

project.json 与以下dependencies 部分的用法：

{
  "dependencies": {
    "Microsoft.AspNet.Diagnostics": "1.0.0-rc1-final",
    "Microsoft.AspNet.IISPlatformHandler": "1.0.0-rc1-final",
    "Microsoft.AspNet.Mvc": "6.0.0-rc1-final",
    "Microsoft.AspNet.Mvc.TagHelpers": "6.0.0-rc1-final",
    "Microsoft.AspNet.Server.Kestrel": "1.0.0-rc1-final",
    "Microsoft.AspNet.StaticFiles": "1.0.0-rc1-final",
    "Microsoft.AspNet.Tooling.Razor": "1.0.0-rc1-final",
    "Microsoft.Extensions.Configuration.FileProviderExtensions": "1.0.0-rc1-final",
    "Microsoft.Extensions.Configuration.Json": "1.0.0-rc1-final",
    "Microsoft.Extensions.Logging": "1.0.0-rc1-final",
    "Microsoft.Extensions.Logging.Console": "1.0.0-rc1-final",
    "Microsoft.Extensions.Logging.Debug": "1.0.0-rc1-final",
    "Microsoft.Extensions.DependencyInjection": "1.0.0-rc1-final",
    "Microsoft.Extensions.CodeGenerators.Mvc": "1.0.0-rc1-final",
    "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.0.0-rc1-final",
    "EntityFramework.MicrosoftSqlServer": "7.0.0-rc1-final",
    "EntityFramework.MicrosoftSqlServer.Design": "7.0.0-rc1-final",
    "EntityFramework.Commands": "7.0.0-rc1-final",
    "System.Net.Http": "4.0.1-beta-23516",
    "Microsoft.Net.Http": "2.2.29",
    "Newtonsoft.Json": "8.0.1"
  },
  "commands": {
    "web": "Microsoft.AspNet.Server.Kestrel",
    "ef": "EntityFramework.Commands"
  },
  "frameworks": {
    "dnx451": { },
    "dnxcore50": { }
  }
}

从

修复appsettings.json

{
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Verbose",
      "System": "Information",
      "Microsoft": "Information"
    },
    "Data": {
        "DefaultConnection":{
            "ConnectionString": "Server=localhost;Database=BookStore;User Id=sa; Password=******;Trusted_Connection=true;"
        }
    }
  }
}

到

{
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Verbose",
      "System": "Information",
      "Microsoft": "Information"
    }
  },
  "Data": {
    "DefaultConnection": {
      "ConnectionString": "Server=localhost;Database=BookStore;User Id=sa; Password=******;Trusted_Connection=true;"
    }
  }
}

（Data 不应不在Logging下）

以及下面Startup.cs的用法

using apiservice.Models;
using Microsoft.AspNet.Builder;
using Microsoft.AspNet.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Data.Entity;


namespace apiservice
{
    public class Startup
    {
        public static IConfigurationRoot Configuration {get; set;}

        public Startup(IHostingEnvironment env)
        {
            // Set up configuration sources.
            var builder = new ConfigurationBuilder()
                .AddJsonFile("appsettings.json")
                .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
                .AddEnvironmentVariables();
            Configuration = builder.Build();
        }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            // Add framework services.
            services.AddEntityFramework()
                .AddSqlServer()
                .AddDbContext<BookContext>(options => 
                    options.UseSqlServer(Configuration["Data:DefaultConnection:ConnectionString"])
                );

            services.AddMvc();
        }

        public void Configure(IApplicationBuilder app, ILoggerFactory loggerFactory)
        {
            loggerFactory.AddConsole(Configuration.GetSection("Logging"));
            loggerFactory.AddDebug();

            // we need to execute the following two commands before

            //    dnu restore
            //    dnx ef migrations add Initial
            //    dnx ef database update   

            // For more details on creating database during deployment see http://go.microsoft.com/fwlink/?LinkID=615859
            try
            {
                using (var serviceScope = app.ApplicationServices.GetRequiredService<IServiceScopeFactory>()
                    .CreateScope())
                {
                    serviceScope.ServiceProvider.GetService<BookContext>()
                         .Database.Migrate();
                }
            }
            catch { }

            app.UseIISPlatformHandler();

            app.UseStaticFiles();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
            });

            SampleData.Initialize(app.ApplicationServices);
        }

        // Entry point for the application.
        public static void Main(string[] args) => WebApplication.Run<Startup>(args);
    }
}

我在Configure 方法内的评论中写道，应该执行命令

dnx ef migrations add Initial
dnx ef database update

在所有包都恢复之后。 dnx ef migrations add Initial 将在项目中创建额外的Migrations 文件夹，其中包含20160101205609_Initial.cs 和BookContextModelSnapshot.cs 等文件。 appsettings.json 中定义的数据库将由dnx ef database update 创建，并在与程序分叉时填充来自SampleData.cs 的测试数据。

顺便说一句，我将package.json 移动到了包文件夹内（与project.json 在同一级别）。您不使用包，但移动使 npm 包在 Visual Studio 中可见和管理。