服务集合 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。要绑定到的模型称为可配置设置。我试图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. ServiceCollection为IOptions返回null，即使GetSection正在工作

我试图遵循这里给出的建议，并将其应用于我自己的应用程序中。经过4个小时的努力，我还是没能让它发挥作用。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ConfigurationSettings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; }
}
}

My ConfigureServices的结构如下：

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"
}
}

当我试图在类中使用它时，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;
}

有人能帮我找出我做错了什么吗？

Answer 1

不确定如何在项目中使用ConfigureServices方法，实际上Startup.cs中的ConfigureServices必须是无参数的，或者只接受一个类型为IServiceCollection的参数。

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);
//...
}
}

还可以更改您的模型设计，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; }
}