在控制器中访问config.json

Question

我正在尝试在我的 config.json 文件中访问值，但是它在我的控制器中返回null值，以及在 startup.cs中进行测试时。

在startup.cs

public Startup(IHostingEnvironment env)
{
    var builder = new ConfigurationBuilder()
        .SetBasePath(env.ContentRootPath)
        .AddJsonFile("config.json", optional: true, reloadOnChange: true)
        .AddJsonFile($"config.{env.EnvironmentName}.json", optional: true)
        .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
        .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true);
    builder.AddEnvironmentVariables();
    Configuration = builder.Build();      
}
public void ConfigureServices(IServiceCollection services)
{
  /*...
  ...*/
    services.AddOptions();
    services.Configure<AppSettings>(Configuration.GetSection("MicrosoftAzureStorage"));

在控制器中

public class TestController : Controller
{
    private string _token;
    public IActionResult Index()
    {
        return View();
    }
    public TestController(IOptions<AppSettings>settings)
    {
        _token = settings.Value.token; //returns Null
    }

AppSettings.cs

public class AppSettings
{
    public string ApplicationName { get; set; }
}

config.json

{
    "MicrosoftAzureStorage": 
    {
        "AzureStorageConnectionString": "RandomConnectionString"
    }
}

Answer 1

您正在添加jsonfiles而不知道它们确实存在。

.AddJsonFile("config.json", optional: true, reloadOnChange: true)

如果您更改可选：真实为false，则可能会得到异常。由于我缺少一条信息，因此请在项目中发布。json我无法确定。查看PublishOptions，您可能必须添加AppSettings.json：

  "publishOptions": {
    "include": [
      "wwwroot",
      "appsettings.json",
      "web.config"
    ]
  },

Answer 2

属性名称必须匹配JSON文件中的密钥名称。请参阅此处的类似示例：将加载配置添加到ASP.NET Core

Answer 3

我在应用程序中一直使用的代码片段。

在startup.cs

中

 public Startup(IHostingEnvironment env)
    {
        var builder = new ConfigurationBuilder()
            .SetBasePath(env.ContentRootPath)
            .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
            .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
            .AddJsonFile("secondary.json", optional: false, reloadOnChange: true)
            .AddEnvironmentVariables();
        Configuration = builder.Build();
    }

在控制器方法或辅助类中。

var builder = new ConfigurationBuilder();
builder.AddJsonFile(Directory.GetCurrentDirectory() + "/secondary.json");
var configuration = builder.Build();
var myValue = configuration["MicrosoftAzureStorage:AzureStorageConnectionString"];