c# - ASP.NET MVC 6 Controller 工厂

Question

我想从数据库(ASP.NET MVC 6 vNext)创建 Controller Action 。我有表 Controller 和 Action 操作表具有属性 { ViewPath, ActionName } 其中 actionName 是 {Controller}/{ActionName}我想要这样构建页面。我怎样才能做到？我有 MVC 4 的类(class)，但我需要将其重写为 MVC 6

public class ITSDefaultController : DefaultControllerFactory
    {

        public override IController CreateController(System.Web.Routing.RequestContext requestContext, string controllerName)
        {
            try
            {
                return base.CreateController(requestContext, controllerName) as Controller;

            }
            catch (Exception)
            {
                Controller controller = new ITSControllerBase();
                using (var db = new ITS.Database.DatabaseDataContext())
                {
                    string action = requestContext.RouteData.Values["action"] as string;
                    DynamicAction dynamicAction = null;
                    if (!db.Controllers.Any(x => x.ControllerName == controllerName && x.Views.Any(v => v.ViewName == action)))
                    {
                        dynamicAction = Actions["NotFound"].First();
                        requestContext.RouteData.Values["controller"] = "NotFound";
                        requestContext.RouteData.Values["action"] = "Index";
                    }
                    else
                    {
                        dynamicAction = new DynamicAction()
                        {
                            ActionName = db.Views.First(d => d.ViewName == action && d.Controller.ControllerName == controllerName).ViewName,
                            Result = () => new ViewResult()
                        };
                    }


                    if (dynamicAction != null)
                    {
                        controller.ActionInvoker = new DynamicActionInvoker() { DynamicAction = dynamicAction };
                    }

                    return controller;
                }

            }
        }
        public override void ReleaseController(IController controller)
        {
            base.ReleaseController(controller);
        }
        public static ConcurrentDictionary> Actions = new ConcurrentDictionary>();
    }

Answer 1

其实我也有同样的需要将Mvc管道组件替换成一些自定义的，我发现IControllerFactory和IControllerActivator以及它们的默认实现还是一样的，然后经验就是将Mvc 6的DefaultControllerFactory替换成CustomControllerFactory，我在 ConfigureServices 的启动类上做了一些测试:

    public void ConfigureServices(IServiceCollection services)
    {
       services.AddMvc();
       var serviceDescriptor = services.FirstOrDefault(s => s.ServiceType.FullName.Contains("IControllerFactory"));
       var serviceIndex = services.IndexOf(serviceDescriptor);
       services.Insert(serviceIndex, new ServiceDescriptor(typeof(IControllerFactory), typeof(CustomControllerFactory), ServiceLifeTime.Singleton));
       services.RemoveAt(serviceIndex + 1);
    }

大功告成，你也可以给IServiceCollection接口(interface)添加一个扩展方法:

    public static class ServiceCollectionExtensions
    {
        public static void(this IServiceCollection services, Type serviceType, Type implementationType, ServiceLifetime serviceLifetime = ServiceLifetime.Singleton)
        {
            var serviceDescriptor = services.FirstOrDefault(s => s.ServiceType == serviceType);
            var serviceIndex = services.IndexOf(serviceDescriptor);
            services.Insert(serviceIndex, new ServiceDescriptor(serviceType, implementationType, serviceLifetime));
            services.RemoveAt(serviceIndex + 1);
        }
    }

修改后你可以像这样简单地使用它:

    ......
    services.AddMvc();
    services.ReplaceService(typeof(IControllerActivator), typeof(CustomControllerActivator));
    services.ReplaceService(typeof(IControllerFactory), typeof(CustomControllerFactory));
    ......

然后就可以替换Mvc 6 Pipeline上的任何组件；