将 .NET Core IConfiguration 注入到 Singleton 中

Question

我想在我的应用程序中使用以下 Singleton 类：

public sealed class AppSettings
{
    private static readonly Lazy<AppSettings> _lazy =
        new Lazy<AppSettings>(() => new AppSettings());

    private AppSettings()
    {
        // I want to inject this
        var builder = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile($"appsettings.json", optional: true, reloadOnChange: true);

        Config = builder.Build();
    }

    public static AppSettings Instance => _lazy.Value;

    public IConfigurationRoot Config { get; }
}

我想注入 IConfiguration 而不是将其构建在其中。我怎样才能做到这一点？

Answer 1

您不需要创建自己的单例类。相反，创建一个普通的类并将其作为单例注册/添加到 DI 容器中：

public sealed class AppSettings
{
    private IConfiguration _configuration;

    public AppSettings(IConfiguration configuration)
    {
        _configuration = configuration;
    }

    ...
}

然后在ConfigureServices方法中使用

// IConfigurationRoot ConfigureServices;

services.AddSingleton(new AppSettings(Configuration));