C# .net core 3.1 WorkerService未加载配置选项/设置

使用WorkerService（.net core 3.1）的库存项目模板，我无法使

IOptions

正常工作

这是一个最小的复制：

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .UseConsoleLifetime()
            .ConfigureServices((hostContext, services) =>
            {
                services.AddOptions();
                services.AddHostedService<Worker>();
            });
}

工人

public class Worker : BackgroundService
{
    private readonly mailsettings _mailsettings;

    public Worker(IOptions<mailsettings> mailsettings)
    {
        _mailsettings = mailsettings.Value;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        while (!stoppingToken.IsCancellationRequested)
        {
            Console.WriteLine($"MailSettings SmtpServer: \"{(_mailsettings.smtpserver ?? "**null**")}\"");
            Console.WriteLine(Directory.GetCurrentDirectory());
            await Task.Delay(1000, stoppingToken);
        }
    }
}

这将写：

邮件设置SmtpServer:null“

到控制台。它应该写

“mail.com”

---

我已经猜了很多了。。。但是哪儿也去不了

邮件设置未配置到服务集合中，因此DI容器无法解析

IOPtions

调用服务集合上的

Configure

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .UseConsoleLifetime()
        .ConfigureServices((hostContext, services) => {
            services
                .AddOptions()
                .Configure<mailsettings>(hostContext.Configuration.GetSection("mailsettings"))
                .AddHostedService<Worker>();
        });

公共静态IHostBuilder CreateHostBuilder（字符串[]args）=>
Host.CreateDefaultBuilder（args）
.UseConsoleLifetime（）文件
.ConfigureServices（（主机上下文，服务）=>{
服务
.AddOptions（）
.Configure（hostContext.Configuration.GetSection（“邮件设置”））
.AddHostedService（）；
});

参考文献

参考文献

{
  "mailsettings": {
    "smtpserver": "mail.com"
  }
}

public static IHostBuilder CreateHostBuilder(string[] args) =>
    Host.CreateDefaultBuilder(args)
        .UseConsoleLifetime()
        .ConfigureServices((hostContext, services) => {
            services
                .AddOptions()
                .Configure<mailsettings>(hostContext.Configuration.GetSection("mailsettings"))
                .AddHostedService<Worker>();
        });