在 MVC6 中读取 config.json 时抛出 NullReferenceException

Question

我正在开发 MVC6 网络应用程序。我的 Startup.cs 有以下代码-

public class Startup
{
    public static Microsoft.Framework.ConfigurationModel.IConfiguration Configuration { get; set; }

    public Startup(IHostingEnvironment env)
    {
       //following line throws NullReferenceException
       Configuration = new Configuration().AddJsonFile("config.json").AddEnvironmentVariables();
    }
}

config.json-

{
    "Data": {
        "DefaultConnection": {
            "ConnectionString": "Server=(localdb)\MSSQLLocalDB;Database=_CHANGE_ME;Trusted_Connection=True;"
         }
     }
}

有什么帮助吗？

UPDATE: This question is not all about NullReferenceException. In ASP.NET-5 MVC-6, config.json is a new addition. I am using the code as it is found in several blogs. Here are few links-

• http://bitoftech.net/2014/11/18/getting-started-asp-net-5-mvc-6-web-api-entity-framework-7/
• https://github.com/aspnet/MusicStore/blob/master/src/MusicStore/Startup.cs
• http://forums.asp.net/t/1999143.aspx?How+to+configure+connection+string+in+MVC+6+in+ASP+NET+vNext
• http://blog.developers.ba/read-config-file-in-asp-net-vnext/

Answer 1

如果您使用的是 Visual Studio 的 RTM 版本，则必须使用 asp.net 的 beta5 修订版。在此版本中，配置的命名空间已更改。

编辑： 你必须添加这个包：Microsoft.Framework.Configuration.Json

此代码一定适合您：

using Microsoft.Framework.Configuration;
using Microsoft.Framework.Runtime;

namespace Test
{
    public class Startup
    {
        public IConfiguration Configuration { get; set; }

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

            Configuration = builder.Build();
        }
    }
}