Question

我正在摆弄EntityFramework 7和ASP.NET 5 / vNext。我关注this tutorial。但是，当我尝试从config.json文件中获取连接字符串时，我遇到了一个问题：

'IConfiguration' does not contain a definition for 'Get' and no extension method 'Get' accepting a first argument of type 'IConfiguration' could be found (are you missing a using directive or an assembly reference?)

我不认为我错过了一个引用，但这里是project.json依赖项部分：

  "dependencies": {
    "Microsoft.AspNet.Diagnostics": "1.0.0-beta5",
    "Microsoft.AspNet.Mvc": "6.0.0-beta5",
    "Microsoft.AspNet.Server.IIS": "1.0.0-beta5",
    "Microsoft.AspNet.Server.WebListener": "1.0.0-beta5",
    "Microsoft.AspNet.StaticFiles": "1.0.0-beta5",
    "System.Net.Http": "4.0.0-beta-23019",
    "Microsoft.AspNet.WebApi": "5.2.3",
    "Microsoft.AspNet.WebUtilities": "1.0.0-beta5",
    "Microsoft.Framework.Configuration.Json": "1.0.0-beta5",
    "Microsoft.Owin.Security": "3.0.1",
    "Microsoft.AspNet.Hosting": "1.0.0-beta5",
    "Kestrel": "1.0.0-*",
    "Microsoft.AspNet.WebApi.Owin": "5.2.3",
    "Microsoft.Owin.Security.OAuth": "3.0.1",
    "Microsoft.AspNet.Mvc.Core": "6.0.0-beta5",
    "Microsoft.AspNet.Mvc.WebApiCompatShim": "6.0.0-beta5",
    "Microsoft.AspNet.Identity.Owin": "2.2.1",
    "Microsoft.AspNet.Identity.EntityFramework": "3.0.0-beta5",
    "EntityFramework.SqlServer": "7.0.0-beta8-15186",
    "EntityFramework.Commands": "7.0.0-beta5",
    "Microsoft.AspNet.Http.Abstractions": "1.0.0-beta8-15078",
    "Microsoft.Framework.Logging.Console": "1.0.0-beta8-15086"
  }

以下是导致问题的代码（在Startup.cs中）：

public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc();

            services.AddEntityFramework()
                    .AddSqlServer()
                    .AddDbContext<RibandelleDbContext>(options =>
                    {
                        options.UseSqlServer(Configuration.Get("Data:ConnectionString"));
                    });            
            }

Configuration.Get("Data:ConnectionString")位返回上面的错误。我已经尽力将代码与文档样本进行比较，看起来与我完全相同。我无法弄清楚Get（）方法的来源。

我怎样才能正确弄清楚我错过了什么？

Answer 1

IConfiguration 应该在string Get(string key)包中使用"Microsoft.Framework.Configuration.Json": "1.0.0-beta6"方法

我不确定在beta5中。

我刚刚测试了最新版本：

"Microsoft.Framework.Configuration.Json": "1.0.0-beta8-15562"

它也已从那里删除。

根据Peter的评论，您可以以索引方式访问json属性。

示例：

public class Startup { public IConfiguration Configuration {get;私人集; }

public Startup(IHostingEnvironment env, IApplicationEnvironment appEnv)
{
    var configurationBuilder = new ConfigurationBuilder(appEnv.ApplicationBasePath)
                        .AddJsonFile("config.json")
                        .AddEnvironmentVariables();
    Configuration = configurationBuilder.Build();

    string test = Configuration["Data:ConnectionString"]; //this reads the property
}

public void ConfigureServices(IServiceCollection services)
{
    //services.AddMvc();

    services.AddEntityFramework()
        .AddSqlServer()
        .AddDbContext<RibandelleDbContext>(options =>
        {
            options.UseSqlServer(Configuration["Data:ConnectionString"]);
        });
}

public void Configure(IApplicationBuilder app)
{
    app.Run(async (context) =>
    {
        await context.Response.WriteAsync("Hello World!");
    });
}

}

假设您有一个config.json文件，其中的数据连接字符串如下所示：

{
  "Data": {
    "ConnectionString": "Server=.;Database=Your_Database_Name;Trusted_Connection=True;MultipleActiveResultSets=true"
  }
}

Answer 2

当我遇到类似的错误时，我刚从框架中删除了dnxcore50 - 一些编译错误引用了dnxcore50。

"frameworks": {
  "dnx451": {
    "dependencies": {
      "RRStore.EF": "1.0.0-*"
    }
  },
  "dnxcore50": { }
},

IConfiguration不包含Get（）（EF7，vNext）

2 个答案: