获取控制器中当前的IServiceScope

Question

IServiceScope如何获取控制器中当前（每个请求）的实例？在服务中？

计划是用它来解析属于同一范围的服务。

Answer 1

在控制器中获取一个实例...：

1. 无需IHttpContextAccessor在Controller内使用。已经有适合您的HttpContext房产了。如果你想访问HttpContext，只需

   // no need to use IHttpContextAccessor.HttpContext
   var svc = HttpContext.RequestServices.GetService<MyService>();
   

2. 或者作为替代方案，直接注入IServiceProvider：

   public class MyController : Controller
   {
       private IServiceProvider _sp;
       public MyController(IServiceProvider sp)
       {
           this._sp = sp;
       }
   }
   

   当你想要一个小范围时，你可以如下创建：

   public IActionResult MyActoin()
   {
       // create a more small scope
       using (var scope = this._sp.CreateScope())
       {
           var sp = scope.ServiceProvider;
           // now you get the services from this small scope
           var svc1 = sp.GetRequiredService<MyService1>();
           var svc2 = sp.GetRequiredService<MyService2>();
           //...
       }
       return new JsonResult("it works");
   }
   

3. 特别是，如果所需服务的范围恰好是请求范围，则只需将它们全部注入：

   public class MyController : Controller
   {
       private IServiceProvider _sp;
       private readonly MyService1 _service1;
       private readonly MyService2 _service2;
   
       public MyController(IServiceProvider sp, MyService1 service1, MyService2 service2,...)
       {
           this._sp = sp;
           this._service1 = service1;
           this._service2 = service2;
       }
   

Answer 2

一种解决方案是在控制器的构造函数中请求IHttpContextAccessor contextAccessor，然后从中解析所需的服务：

var svc = contextAccessor.HttpContext.RequestServices.GetService<MyService>();