使用IOption从asp.net核心3.1Web api的配置中读取connectionString

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=myServerAddress;Database=myDatabase;User Id=myUsername;Password=myPassword;"
  }
}

using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;

public class Startup
{
    private IConfiguration Configuration { get; }

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

    public void ConfigureServices(IServiceCollection services)
    {
        services.Configure<ConnectionStrings>(Configuration.GetSection("ConnectionStrings"));

        // 其他服务配置
    }
}

public class ConnectionStrings
{
    public string DefaultConnection { get; set; }
}

using Microsoft.Extensions.Options;

public class MyController : ControllerBase
{
    private readonly string _connectionString;

    public MyController(IOptions<ConnectionStrings> options)
    {
        _connectionString = options.Value.DefaultConnection;
    }

    // 其他操作方法
}