.NET Core-自定义配置数据源

 //
    // 摘要:
    //     Represents a source of configuration key/values for an application.
    public interface IConfigurationSource
    {
        //
        // 摘要:
        //     Builds the Microsoft.Extensions.Configuration.IConfigurationProvider for this
        //     source.
        //
        // 参数:
        //   builder:
        //     The Microsoft.Extensions.Configuration.IConfigurationBuilder.
        //
        // 返回结果:
        //     An Microsoft.Extensions.Configuration.IConfigurationProvider
        IConfigurationProvider Build(IConfigurationBuilder builder);
    }

   //
    // 摘要:
    //     Provides configuration key/values for an application.
    public interface IConfigurationProvider
    {
        //
        // 摘要:
        //     Returns the immediate descendant configuration keys for a given parent path based
        //     on this Microsoft.Extensions.Configuration.IConfigurationProviders data and the
        //     set of keys returned by all the preceding Microsoft.Extensions.Configuration.IConfigurationProviders.
        //
        // 参数:
        //   earlierKeys:
        //     The child keys returned by the preceding providers for the same parent path.
        //
        //   parentPath:
        //     The parent path.
        //
        // 返回结果:
        //     The child keys.
        IEnumerable<string> GetChildKeys(IEnumerable<string> earlierKeys, string parentPath);
        //
        // 摘要:
        //     Returns a change token if this provider supports change tracking, null otherwise.
        //
        // 返回结果:
        //     The change token.
        IChangeToken GetReloadToken();
        //
        // 摘要:
        //     Loads configuration values from the source represented by this Microsoft.Extensions.Configuration.IConfigurationProvider.
        void Load();
        //
        // 摘要:
        //     Sets a configuration value for the specified key.
        //
        // 参数:
        //   key:
        //     The key.
        //
        //   value:
        //     The value.
        void Set(string key, string value);
        //
        // 摘要:
        //     Tries to get a configuration value for the specified key.
        //
        // 参数:
        //   key:
        //     The key.
        //
        //   value:
        //     The value.
        //
        // 返回结果:
        //     True if a value for the specified key was found, otherwise false.
        bool TryGet(string key, out string value);
}

class MyConfigurationProvider : ConfigurationProvider
{
    Timer timer;
    public MyConfigurationProvider():base()
    {
        timer = new Timer() ;
        timer.Elapsed += Timer_Elapsed;
        timer.Interval = 3000;
        timer.Start();
    }
    private void Timer_Elapsed(object sender, ElapsedEventArgs e)
    {
        Load(true);
    }
    public override void Load()
    {
        Load(false);
    }
    private void Load(bool reload)
    {
        this.Data["time"] = System.DateTime.Now.ToString();
        if (reload)
        {
            base.OnReload();
        }
    }
}

class MyConfigurationSource : IConfigurationSource
{
    public IConfigurationProvider Build(IConfigurationBuilder builder)
    {
        return  new MyConfigurationProvider();
    }
}

public static class MyConfigurationSourceExtension
{
    public static IConfigurationBuilder AddSource( this IConfigurationBuilder configurationBuilder)
    {
        MyConfigurationSource myConfigurationSource = new MyConfigurationSource();
        configurationBuilder.Add(myConfigurationSource);
        return configurationBuilder;
    }
}

static void Main(string[] args)
{
    IConfigurationBuilder configurationBuilder = new ConfigurationBuilder();
    //configurationBuilder.Add(new MyConfigurationSource());
    configurationBuilder.AddSource();
    IConfigurationRoot configurationRoot= configurationBuilder.Build();
    ChangeToken.OnChange(()=> configurationRoot.GetReloadToken(), () =>
    {
        Console.WriteLine(configurationRoot["time"]);
    });
    Console.ReadKey();
}