将方法返回的值传递给操作过滤器

Question

我将_serviceOne 注入到我的控制器中，该控制器有一个返回int 值的方法。我正在尝试将此值传递给我的自定义操作过滤器。

这不起作用，我收到错误：An object reference is required for the non-static field, method, or property 'NameController._serviceOne' 我尝试在其中设置 Number = _serviceOne.GetIntNumber。

我知道我可以访问控制器内部的值（例如：控制器参数、ViewBag、ViewData、控制器中的变量），但我想将该值传递给CustomActionFilter 过滤器的@987654326 @属性。

过滤器和服务方法按我想要的方式工作，但它不会让我将_serviceOne.GetIntNumber 的值传递到过滤器。为什么这不起作用，我怎样才能使它起作用？

NameController.cs：

public class NameController : Controller
{
    private readonly ServiceOne _serviceOne;

    public NameController(ServiceOne serviceOne)
    {
        _serviceOne = serviceOne;
    }

    [CustomActionFilter(Name = "CorrectName", Number = _serviceOne.GetIntNumber)] //does not work
    [HttpGet]
    public IActionResult Index()
    {
        return View();
    }
}

CustomActionFilter.cs：

public class CustomActionFilter : ActionFilterAttribute
{
    public string Name { get; set; }
    public int Number { get; set; }

    public override void OnActionExecuted(ActionExecutedContext context)
    {
        if (Name == "CorrectName" && Number == 1) {
            RouteValueDictionary routeDictionary = new RouteValueDictionary { { "action", "SomeAction" }, { "controller", "NameController" } };
            context.Result = new RedirectToRouteResult(routeDictionary);
        }

        base.OnActionExecuted(context);
    }
}

Answer 1

属性是在编译时创建的，因此无法在构造函数中传递它们的运行时值。

相反，您可以访问NameController 的服务实例，如下所示：

public class NameController : Controller
{
    private readonly ServiceOne _serviceOne;

    public ServiceOne ServiceOne => _serviceOne;

    public NameController(ServiceOne serviceOne)
    {
        _serviceOne = serviceOne;
    }
}

public class CustomActionFilter : ActionFilterAttribute
{
    public string Name { get; set; }
    public int Number { get; set; }

    public override void OnActionExecuted(ActionExecutedContext context)
    {
        var controller = context.Controller as NameController;
        var service = controller.ServiceOne;
        //Use the service here
    }
}

另见Access a controller's property from an action filter