从appsettings.json获取值

{
  "AppName": "MyApp"
}

using Microsoft.Extensions.Configuration;

public class Startup
{
    private IConfiguration Configuration { get; }

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

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddSingleton(Configuration);
    }
    
    // ...
}

using Microsoft.Extensions.Configuration;

public class MyClass
{
    private IConfiguration Configuration { get; }

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

    public void MyMethod()
    {
        string appName = Configuration["AppName"];
        // 使用配置项的值进行后续逻辑处理
    }
}

string appName = Configuration["AppName"];