c# - ServiceCollection IOptions<> 无法正确绑定

Question

我正在尝试绑定一些可配置的设置。这些值是通过 app-settings.local.json 提供的。要绑定的模型称为可配置设置。我尝试遵循一些教程并解决问题：

1. https://andrewlock.net/how-to-use-the-ioptions-pattern-for-configuration-in-asp-net-core-rc2/
2. https://github.com/aspnet/Configuration/issues/411
3. 无法从 .NET Core 项目中的 JSON appsettings 文件设置配置
4. 即使 GetSection 正在工作，ServiceCollection 也会为 IOptions 返回 null

我试图遵循此处给出的建议并将其应用到我自己的应用程序中。经过 4 小时的尝试，我无法让它工作。要么我缺乏实现这一点所需的基本知识，要么我忽略了一些东西。

我的 ConfigurableSettings 类的结构如下：

    public class ConfigurableSettings
    {
        public AppSettings _AppSettings;
        public DgeSettings _DgeSettings;
        
        public class AppSettings
        {
            [JsonProperty("SoftDelete")] 
            public bool SoftDelete { get; set; }
        }

        public class DgeSettings
        {
            [JsonProperty("zipFileUrl")] 
            public string zipFileUrl { get; set; }

            [JsonProperty("sourceFileUrl")] 
            public string sourceFileUrl { get; set; }
        }
    }

我的 ConfigureServices 结构如下：

    public static void ConfigureServices(IServiceCollection serviceCollection, string[] args)
        {
            var serviceCollection = new ServiceCollection(); 
            
            serviceCollection.AddOptions();
            
            var configuration = new ConfigurationBuilder()
                                .SetBasePath(Directory.GetCurrentDirectory())
                                .AddJsonFile("app-settings.local.json", true)
                                .AddJsonFile("app-settings.json", false)
                                .Build();

            serviceCollection.Configure<ConfigurableSettings>(options => configuration.GetSection("AppSettings").Bind(options));
            serviceCollection.Configure<ConfigurableSettings>(options => configuration.GetSection("DgeSettings").Bind(options));

            var services = serviceCollection.BuildServiceProvider();
            var options = services.GetService<IOptions<ConfigurableSettings>>();

            serviceCollection.AddLogging(loggingBuilder =>
            {
                loggingBuilder.AddConfiguration(configuration.GetSection("Logging"));
                loggingBuilder.AddConsole();
                loggingBuilder.AddDebug();
            });

            serviceCollection.AddServices(configuration);
            serviceCollection.AddNopCommerceServices(configuration);

            serviceCollection.AddTransient<Comparator>();
            serviceCollection.AddTransient<UpdateManager>();
            serviceCollection.AddTransient<DgeRequestAuthenticator>();
            serviceCollection.AddTransient<ISourceConnector, DgeConnector>();
            serviceCollection.AddTransient<IDestinationConnector, NopCommerceConnector>();
        }

我的 app-settings.local.json 配置如下：

{
  "AppSettings": {
    "SoftDelete": true
  },

  "DgeSettings": {
    "zipFileUrl" : "www.example-url.com",
    "sourceFileUrl" : "www.example-url.com"
  }
}

当我尝试在类中使用它时，我在构造函数中调用它，如下所示：

private readonly ConfigurableSettings _settings;
        
        public AlphaBetaService(IOptions<ConfigurableSettings> settings)
        {
            _settings = settings.Value;
        }
    

有人可以帮我找出我做错了什么吗？

Answer 1

不确定您如何ConfigureServices在项目中使用方法，实际上ConfigureServicesStartup.cs 必须是无参数或仅采用一个类型的参数IServiceCollection。

更改您的 ConfigureServices，如下所示：

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        var configuration = new ConfigurationBuilder()
                            .SetBasePath(Directory.GetCurrentDirectory())
                            .AddJsonFile("app-settings.local.json", true)
                            .Build();
        services.Configure<ConfigurableSettings>(configuration);

        //...
    }
}

还要更改您的模型设计，如下所示：

public class ConfigurableSettings
{
    public AppSettings AppSettings{ get; set; }
    public DgeSettings DgeSettings { get; set; }        
}
public class AppSettings
{
    [JsonProperty("SoftDelete")]
    public bool SoftDelete { get; set; }
}

public class DgeSettings
{
    [JsonProperty("zipFileUrl")]
    public string zipFileUrl { get; set; }

    [JsonProperty("sourceFileUrl")]
    public string sourceFileUrl { get; set; }
}