如何在 DotNet 核心依赖注入中访问 Services.Configure<MyOptions> 中的选项对象？

Question

我对依赖注入比较陌生。我有以下代码：

 static void Main(string[] args)
        {
            
            var hostBuilder = new HostBuilder()
               .UseConsoleLifetime()
               .ConfigureServices((hostContext, services) =>
               {
                   services.AddFtpServer(opt => opt.UseDotNetFileSystem()).AddHostedService<HostedFtpService>();
                   services.AddSingleton<IMembershipProvider, CustomMembershipProvider>();
                   services.Configure<FtpServerOptions>(opt => opt.Port = 33999);
                });
            var host = hostBuilder.Build();

            var Item1 = host.Services.GetService<IMembershipProvider>(); //This works, I can get the new CustomMembershipProvider Object
            var Item2 = host.Services.GetService<FtpServerOptions>(); //This does NOT work....


        }

我可以访问 CustomMembershipProvider 对象，但是...

如何访问 FtpServerOptions 对象？

下面是 FtpServerOptions 类

public class FtpServerOptions
        {
            public string? ServerAddress { get; set; }
            public int Port { get; set; } = 21;
            public int MaxActiveConnections { get; set; }
            public TimeSpan? ConnectionInactivityCheckInterval { get; set; } = TimeSpan.FromMinutes(1);
        }

Answer 1

试试这个：

var Item2 = host.Services.GetService<IOptions<FtpServerOptions>>(); 

并获取 FtpServerOptions：

var  options = Item2.Value