从appsettings获取值。.net core中的Json

不确定我在这里错过了什么，但我无法从我的应用程序设置中获得值。Json在我的。net核心应用程序。我有我的appsettings。json:

{
    "AppSettings": {
        "Version": "One"
    }
}

启动:

public class Startup
{
    private IConfigurationRoot _configuration;
    public Startup(IHostingEnvironment env)
    {
        _configuration = new ConfigurationBuilder()
    }
    public void ConfigureServices(IServiceCollection services)
    {
      //Here I setup to read appsettings        
      services.Configure<AppSettings>(_configuration.GetSection("AppSettings"));
    }
}

模型:

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

控制器:

public class HomeController : Controller
{
    private readonly AppSettings _mySettings;

    public HomeController(IOptions<AppSettings> settings)
    {
        //This is always null
        _mySettings = settings.Value;
    }
}

_mySettings总是空的。我是不是遗漏了什么?

当前回答

ASP。NET Core 3.1你可以遵循以下指南:

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/?view=aspnetcore-3.1

当您创建一个新的ASP。在Program.cs中，你会有如下的配置行:

Host.CreateDefaultBuilder(args)

这将启用以下功能:

ChainedConfigurationProvider : Adds an existing IConfiguration as a source. In the default configuration case, adds the host configuration and setting it as the first source for the app configuration. appsettings.json using the JSON configuration provider. appsettings.Environment.json using the JSON configuration provider. For example, appsettings.Production.json and appsettings.Development.json. App secrets when the app runs in the Development environment. Environment variables using the Environment Variables configuration provider. Command-line arguments using the Command-line configuration provider.

这意味着您可以注入IConfiguration并使用字符串键获取值，甚至是嵌套值。像IConfiguration“父母:孩子”;

例子:

appsettings.json

{
  "ApplicationInsights":
    {
        "Instrumentationkey":"putrealikeyhere"
    }
}

WeatherForecast.cs

[ApiController]
[Route("[controller]")]
public class WeatherForecastController : ControllerBase
{
    private static readonly string[] Summaries = new[]
    {
        "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
    };

    private readonly ILogger<WeatherForecastController> _logger;
    private readonly IConfiguration _configuration;

    public WeatherForecastController(ILogger<WeatherForecastController> logger, IConfiguration configuration)
    {
        _logger = logger;
        _configuration = configuration;
    }

    [HttpGet]
    public IEnumerable<WeatherForecast> Get()
    {
        var key = _configuration["ApplicationInsights:InstrumentationKey"];

        var rng = new Random();
        return Enumerable.Range(1, 5).Select(index => new WeatherForecast
        {
            Date = DateTime.Now.AddDays(index),
            TemperatureC = rng.Next(-20, 55),
            Summary = Summaries[rng.Next(Summaries.Length)]
        })
        .ToArray();
    }
}

2020-04-22 09:28:30

其他回答

在Startup类的构造函数中，可以访问appsettings。json和使用注入的IConfiguration对象的许多其他设置:

Startup.cs构造函数

    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;

        //here you go
        var myvalue = Configuration["Grandfather:Father:Child"];

    }

public IConfiguration Configuration { get; }

json的内容

  {
  "Grandfather": {
    "Father": {
      "Child": "myvalue"
    }
  }

2019-01-06 10:22:47

像这样在这里添加所需的键。在这种情况下，它的securecookie:

在startup.cs中添加构造函数公共启动(IConfiguration配置) ｛配置=配置; ｝ public IConfiguration Configuration {get;｝使用Configuration[" secucookie "]访问设置

2021-01-08 06:30:57

花了一个小时试图解决同样的问题，我的解决方案是为appconfig添加PreserveNewest/CopyAlways。csproj中的Json

<None Update="appsettings.json">
  <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
</None>

2022-01-13 10:51:49

ASP。NET Core 3.1你可以遵循以下指南:

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/configuration/?view=aspnetcore-3.1

当您创建一个新的ASP。在Program.cs中，你会有如下的配置行:

Host.CreateDefaultBuilder(args)

这将启用以下功能:

这意味着您可以注入IConfiguration并使用字符串键获取值，甚至是嵌套值。像IConfiguration“父母:孩子”;

例子:

appsettings.json

{
  "ApplicationInsights":
    {
        "Instrumentationkey":"putrealikeyhere"
    }
}

WeatherForecast.cs

[ApiController]
[Route("[controller]")]
public class WeatherForecastController : ControllerBase
{
    private static readonly string[] Summaries = new[]
    {
        "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
    };

    private readonly ILogger<WeatherForecastController> _logger;
    private readonly IConfiguration _configuration;

    public WeatherForecastController(ILogger<WeatherForecastController> logger, IConfiguration configuration)
    {
        _logger = logger;
        _configuration = configuration;
    }

    [HttpGet]
    public IEnumerable<WeatherForecast> Get()
    {
        var key = _configuration["ApplicationInsights:InstrumentationKey"];

        var rng = new Random();
        return Enumerable.Range(1, 5).Select(index => new WeatherForecast
        {
            Date = DateTime.Now.AddDays(index),
            TemperatureC = rng.Next(-20, 55),
            Summary = Summaries[rng.Next(Summaries.Length)]
        })
        .ToArray();
    }
}

2020-04-22 09:28:30

我想最简单的方法就是DI。一个进入控制器的例子。

// StartUp.cs
public void ConfigureServices(IServiceCollection services)
{
    ...
    // for get appsettings from anywhere
    services.AddSingleton(Configuration);
}

public class ContactUsController : Controller
{
    readonly IConfiguration _configuration;

    public ContactUsController(
        IConfiguration configuration)
    {
        _configuration = configuration;

        // sample:
        var apiKey = _configuration.GetValue<string>("SendGrid:CAAO");
        ...
    }
}

2018-10-26 16:02:49

从appsettings获取值。.net core中的Json

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