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");
        ...
    }
}

再加上David Liang对Core 2.0的回答——

appsettings。json文件链接到ASPNETCORE_ENVIRONMENT变量。

ASPNETCORE_ENVIRONMENT可以设置为任何值，但是框架支持三个值:Development、Staging和Production。如果没有设置ASPNETCORE_ENVIRONMENT，它将默认为Production。

对于这三个值，这些appsettings.ASPNETCORE_ENVIRONMENT。json文件支持开箱即用- appsettings.Staging。appsettings.Development.json和appsettings.Production.json

以上三个应用程序设置json文件可用于配置多个环境。

示例- appsettings.Staging.json

{
    "Logging": {
        "IncludeScopes": false,
        "LogLevel": {
            "System": "Information",
            "Microsoft": "Information"
        }
    },
    "MyConfig": "My Config Value for staging."
}

使用Configuration["config_var"]检索任何配置值。

public class Startup
{
    public Startup(IHostingEnvironment env, IConfiguration config)
    {
        Environment = env;
        Configuration = config;
        var myconfig = Configuration["MyConfig"];
    }

    public IConfiguration Configuration { get; }
    public IHostingEnvironment Environment { get; }
}

我只是创建了一个静态类，并在Startup.cs中设置了一个配置变量

public static class GlobalConfig { 
    public static IConfiguration config { get; set; } 
}

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        GlobalConfig.config = configuration;

    }
}

然后在任何地方使用它:

var keyVal = GlobalConfig.config["key"];

似乎是访问配置文件并使其在任何地方可用的最简单的方法。

我发现用。net Core 3+最容易做到以下几点。我发现所有使用HostBuilders等的其他方法都有点啰嗦，而且可读性不强。这不是专门针对ASP的。但是你可以调整它…

这里有一个工作示例:https://github.com/NotoriousPyro/PyroNexusTradingAlertBot/blob/develop/PyroNexusTradingAlertBot/Program.cs

创建json:

{
"GlobalConfig": {
    "BlacklistedPairs": [ "USD", "USDT", "BUSD", "TUSD", "USDC", "DAI", "USDK" ]
},
"CoinTrackingConfig": {
    "Cookie1": "",
    "Cookie2": "",
    "ApiKey": "",
    "ApiSecret": "",
    "UpdateJobs": [
    {
        "Name": "Binance",
        "Path": "binance_api",
        "JobId": 42202
    },
    {
        "Name": "Bitfinex",
        "Path": "bitfinex_api",
        "JobId": 9708
    }
    ]
},
"DiscordConfig": {
    "BotToken": ""
}
}

创建json对象的类:

class GlobalConfig
{
    public string[] BlacklistedPairs { get; set; }
}
class CoinTrackingConfig
{
    public string Cookie1 { get; set; }
    public string Cookie2 { get; set; }
    public string ApiKey { get; set; }
    public string ApiSecret { get; set; }
    public List<CoinTrackingUpdateJobs> UpdateJobs { get; set; }
}

class CoinTrackingUpdateJobs
{
    public string Name { get; set; }
    public string Path { get; set; }
    public int JobId { get; set; }
}

class DiscordConfig
{
    public string BotToken { get; set; }
}

创建一个helper类:

private class Config
{
    private IConfigurationRoot _configuration;
    public Config(string config) => _configuration = new ConfigurationBuilder()
            .AddJsonFile(config)
            .Build();

    public T Get<T>() where T : new()
    {
        var obj = new T();
        _configuration.GetSection(typeof(T).Name).Bind(obj);
        return obj;
    }
}

服务提供者选项和服务构造函数:

public class DiscordServiceOptions
{
    public string BotToken { get; set; }
}

public DiscordService(IOptions<DiscordServiceOptions> options, ILogger<DiscordService> logger)
{
    _logger = logger;
    _client = new DiscordSocketClient();
    _client.Log += Log;
    _client.Ready += OnReady;
    _client.Disconnected += OnDisconnected;
    _client.LoginAsync(TokenType.Bot, options.Value.BotToken);
    _client.StartAsync();
}

像这样初始化它(将配置传递给服务提供者- IOptions将在服务构建时传递进来):

static async Task Main(string[] args)
{
    var _config = new Config("config.json");

    var globalConfig = config.Get<GlobalConfig>();
    var coinTrackingConfig = config.Get<CoinTrackingConfig>();
    var discordConfig = config.Get<DiscordConfig>();

    _services = new ServiceCollection()
        .AddOptions()
        .Configure<DiscordServiceOptions>(options =>
        {
            options.BotToken = discordConfig.BotToken;
        })
        .AddSingleton<IDiscordService, DiscordService>()
        .AddLogging(logging =>
        {
            logging.SetMinimumLevel(LogLevel.Trace);
            logging.AddNLog(new NLogProviderOptions
            {
                CaptureMessageTemplates = true,
                CaptureMessageProperties = true
            });
        })
        .BuildServiceProvider();
}

这里是一个关于。net框架和Core: web的抽象。Config, app.config和appsettings.json

    static SafeDictionary<string, string> _appSettings;

    public static SafeDictionary<string, string> AppSettings {
        get {
            if (_appSettings == null)
            {
                _appSettings = ConfigurationManager.AppSettings
                    .ToDictionary()
                    .ToSafe();

                BuildAppSettings( JsonAppSettings, "");

            }

            return _appSettings;
        }
    }


    static SafeDictionary<string, string> _connectionStrings;

    public static SafeDictionary<string, string> ConnectionStrings
    {
        get
        {
            if (_connectionStrings == null)
            {
                _connectionStrings = ConfigurationManager.ConnectionStrings
                    .Cast<ConnectionStringSettings>()
                    .ToDictionary(x => x.Name, x => x.ConnectionString)
                    .ToSafe();

                foreach (var jp in JsonAppSettings["ConnectionStrings"].Cast<JProperty>())
                    _connectionStrings.Add(jp.Name, jp.Value.ToString() );

            }

            return _connectionStrings;
        }
    }

https://github.com/bitministry/common

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"
    }
  }