ASP.Net Core 2.2 - 方法重载出现在 Visual Studio 中，但在运行时不起作用

Question

I am attempting to verify that a user is authorized via a custom policy. I followed the tutorial at Ode To Code to add this functionality to my controller. From within Visual Studio, the code appears to be correct and utilizing a known overload.

Notice that it says that the overload is an "extension". I didn't take much notice of this until I spent 5 hours today trying to solve the following error:

As you can see, it would appear that the overload I'm attempting to use isn't being utilized. Am I doing something wrong here? Is there something special I have to do to include these extended methods? I've attempted cleaning and rebuilding the solution but this hasn't solved the problem.

Answer 1

While you've defined the field for IAuthorizationSerivce , you haven't provided any way for that to be set. You need to define a constructor for the LRController that takes a single parameter of IAuthorizationService , and assign that to the field.

I think there was a definition of that constructor in the tutorial.

Answer 2

Please note the name change: such as the global variable name for IAuthorizationService _authorization has been prefixed with an underscore. Obviously not required, but as a good rule of thumb/good coding standard, IMO. :-)

public class LRController : Controller
{
    private readonly IAuthorizationService _authorization;

    // you're missing this constructor & this pattern is known as Constructor Dependency Injection
    public LRController(IAuthorizationService authorization)
    {
        _authorization = authorization;
    }

    public async Task<RedirectToActionResult> Index()
    {
        var superAdmin = await _authorization.AuthorizeAsync(User, "IsLucky");
        //rest of your code here
    }

}

EDIT

Additionally, if you wanted/needed to inject other interfaces into this controller, you would add it to that LRController constructor. Would look something like this:

public class LRController : Controller
{

    private readonly IAuthorizationService _authorization;
    private readonly IOtherService _otherService;

    public LRController(IAuthorizationService authorization, IOtherService otherService)
    {
        _authorization = authorization;
        _otherService = otherService;
    }

    public async Task<RedirectToActionResult> Index()
    {
        var superAdmin = await _authorization.AuthorizeAsync(User, "IsLucky");
    }

    public async Task Foo()
    {
        await _otherService.Bar();
    }

}