将配置选项从netcoreapp1.1移植到netcoreapp2.0

using Microsoft.Extensions.Configuration;

public class Program
{
    public static void Main(string[] args)
    {
        var config = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("appsettings.json")
            .Build();

        // 将配置选项添加到应用程序的配置中
        var host = new WebHostBuilder()
            .UseKestrel()
            .UseConfiguration(config)
            .UseStartup<Startup>()
            .Build();

        host.Run();
    }
}

using Microsoft.Extensions.Configuration;

public class Startup
{
    private IConfiguration _config;

    public Startup(IConfiguration config)
    {
        _config = config;
    }

    public void ConfigureServices(IServiceCollection services)
    {
        // 注册配置选项
        services.Configure<MyOptions>(_config.GetSection("MyOptions"));
        
        // 其他服务的配置
        // ...
    }
}

public class MyClass
{
    private MyOptions _options;

    public MyClass(IOptions<MyOptions> options)
    {
        _options = options.Value;
    }

    public void DoSomething()
    {
        // 使用配置选项的值
        var connectionString = _options.ConnectionString;
        var logLevel = _options.LogLevel;
        
        // ...
    }
}