讀取.NET6API中的appsettings.{env}.json物件-值為NULL

我正在使用.NET 6創建 API。我有基于環境的appsettings.json檔案。

我也創建了 apt 組態檔launchSettings.json。

我正在嘗試使用Options模式來讀取其中一個控制器內的鍵/值。

NULL我每次都得到這些值。

當我除錯 Program.cs 檔案時，我可以通過下面的代碼行看到正確的值。

builder.Configuration.GetSection(key: "Config").Get<Config>();

請幫忙。使用的代碼如下：

程式.cs：

var builder = WebApplication.CreateBuilder(args);
var configuration = builder.Configuration;

var env = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT");

configuration
    .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
    .AddJsonFile($"appsettings.{env}.json", true, true);

builder.Configuration.GetSection(key: "Config").Get<Config>();

builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services.AddScoped<IProductRepository, ProductRepository>();
builder.Services.AddSingleton<Config>();

組態檔：

public class Config
    {
        public string Environment { get; set; }
        public string Type { get; set; }
    }

ProductsController.cs

    [Route("api/[controller]")]
    [ApiController]
    public class ProductsController : ControllerBase
    {
        private readonly IProductRepository _repository;
        private readonly Config _config;

        public ProductsController(IProductRepository repository,
            IOptions<Config> config)
        {
            _repository = repository;
            _config = config.Value;
        }

        [HttpGet]
        [Route("/configs")]
        public IActionResult GetConfigs()
        {
            var model = new { type = _config.Type, env = _config.Environment };
            return Ok(model);
        }

appsettings.json：

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "Config": {
    "Environment": "local",
    "Type": "local Server"
  }
}

appsettings.Development.json：

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "Config": {
    "Environment": "Development",
    "Type": "Development Server"
  }
}

appsettings.Staging.json：

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "Config": {
    "Environment": "Staging",
    "Type": "Staging Server"
  }
}

啟動設定.json：

 "profiles": {
    "API - Development": {
      "commandName": "Project",
      "dotnetRunMessages": true,
      "launchBrowser": true,
      "launchUrl": "swagger",
      "applicationUrl": "https://localhost:7082;http://localhost:5082",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    },
    "API - Staging": {
      "commandName": "Project",
      "dotnetRunMessages": true,
      "launchBrowser": true,
      "applicationUrl": "https://localhost:5001;http://localhost:5000",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Staging"
      }
    }
}

輸出：

uj5u.com熱心網友回復：

我認為您可能需要使用configuration.GetSectionin Services.Configurewhich 表示從appsettings.json部分注冊Config物件。Config

builder.Services.Configure<Config>(configuration.GetSection("Config"));

uj5u.com熱心網友回復：

我認為您的問題在于：

configuration
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
.AddJsonFile($"appsettings.{env}.json", true, true);

builder.Configuration.GetSection(key: "Config").Get<Config>();

builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services.AddScoped<IProductRepository, ProductRepository>();
builder.Services.AddSingleton<Config>();

您目前正在獲取一個部分Config，然后呼叫Get<>它，但從未將其應用于任何東西（注入）。看起來最后一行會這樣做，但是這個函式沒有引數來提供注入的東西。

你可以：

builder.Services.Configure<Config>(builder.Configuration.GetSection("Config"));

uj5u.com熱心網友回復：

services.AddOptions<Config>()
    .Bind(configuration.GetSection("Config"))
    .ValidateDataAnnotations(); // optionally validate annotations

嘗試使用 AddOptions，這應該會系結。

標籤：C＃ json api .net-6.0

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