ASP.NET MVC的Action攔截器（過濾器）ActionFilter

有時項目要進行客戶端請求(action)進行攔截(過濾)驗證等業務，可以使用攔截器進行實現，所謂的action攔截器也沒有什么的，只是寫一個類，繼承另一個類（System.Web.Mvc.FilterAttribute）和一個接口(System.Web.Mvc.IActionFilter)，至於什么是攔截器這里就不說了，網上很多關於這方面文章。

假如現在有這樣的一個需求：某個action需要登錄才能進行訪問，可以使用action屬性攔截器進行攔截進行驗證

多余的不說了直接上代碼

 寫一個攔截器類：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace AttributeDemo.Common
{
    /// <summary>
    /// Action攔截器
    /// </summary>
    public class ActionFilterAttribute : System.Web.Mvc.FilterAttribute, System.Web.Mvc.IActionFilter
    {
        #region 屬性
        /// <summary>
        /// 記錄是否登陸
        /// </summary>
        public bool IsLogin { get; set; }
        #endregion

        #region 執行action后執行這個方法
        /// <summary>
        /// 執行action后執行這個方法
        /// </summary>
        /// <param name="filterContext"></param>
        void System.Web.Mvc.IActionFilter.OnActionExecuted(System.Web.Mvc.ActionExecutedContext filterContext)
        {

        }
        #endregion


        #region 執行action前執行這個方法 
        /// <summary>
        /// 執行action前執行這個方法
        /// </summary>
        /// <param name="filterContext"></param>
        void System.Web.Mvc.IActionFilter.OnActionExecuting(System.Web.Mvc.ActionExecutingContext filterContext)
        {

            if (!this.IsLogin)  //未登陸 重定向 到登陸頁面
            {
                if (filterContext.HttpContext.Request.IsAjaxRequest())   //判斷是否ajax請求
                {

                    filterContext.Result = new System.Web.Mvc.JsonResult() { Data = new { statusCode = 301 }, ContentEncoding = System.Text.Encoding.UTF8, JsonRequestBehavior = JsonRequestBehavior.AllowGet, ContentType = "json" };
                    return;
                }
                else  //驗證不通過
                {
                    //filterContext.Result = new RedirectToRouteResult(new System.Web.Routing.RouteValueDictionary(new { controller = "ActionFilterTest", action = "Login" }));  //重定向
                    //filterContext.Result = new RedirectToRouteResult(new System.Web.Routing.RouteValueDictionary(new Dictionary<string, object>() { { "controller", "ActionFilterTest" }, { "action", "Login" } }));   //重定向

                    //filterContext.Result = new System.Web.Mvc.RedirectToRouteResult("Default", new System.Web.Routing.RouteValueDictionary(new Dictionary<string, object>() { { "controller", "ActionFilterTest" }, { "action", "Login" } }));    //重定向

                    //filterContext.Result = new System.Web.Mvc.RedirectToRouteResult("Default", new System.Web.Routing.RouteValueDictionary(new Dictionary<string, object>() { { "controller", "ActionFilterTest" }, { "action", "Login" } }),true);  //重定向

                    filterContext.Result = new System.Web.Mvc.RedirectToRouteResult("MyRoute", new System.Web.Routing.RouteValueDictionary(new Dictionary<string, object>() { { "controller", "ActionFilterTest" }, { "action", "Login" } }), true);    //重定向
                    return;
                }

            }

        }
        #endregion

    }
}

請求的控制器類：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace AttributeDemo.Controllers
{
    /// <summary>
    /// 測試Action攔截器
    /// </summary>
    public class ActionFilterTestController : Controller
    {
        //
        // GET: /ActionFilterTest/

        /// <summary>
        /// 測試action攔截器
        /// </summary>
        /// <returns></returns>
        [AttributeDemo.Common.ActionFilter(IsLogin = false)]
        public ActionResult Test()
        {
            return View();
        }

         
        public ActionResult Login()
        {
            return View();
        }

        [AttributeDemo.Common.ActionFilter(IsLogin = true)]
        public ActionResult Index()
        {
            return View();
        }
    }
}

Global.asax類：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Routing;

namespace AttributeDemo
{
    // 注意: 有關啟用 IIS6 或 IIS7 經典模式的說明，
    // 請訪問 http://go.microsoft.com/?LinkId=9394801

    public class MvcApplication : System.Web.HttpApplication
    {
        public static void RegisterGlobalFilters(GlobalFilterCollection filters)
        {
            filters.Add(new HandleErrorAttribute());
        }

        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                "Default", // 路由名稱
                "{controller}/{action}/{id}", // 帶有參數的 URL
                new { controller = "Home", action = "Index", id = UrlParameter.Optional } // 參數默認值
            );
            routes.MapRoute(
                "MyRoute", // 路由名稱
                "{controller}/{action}/{id}", // 帶有參數的 URL
                new { controller = "ActionFilterTest", action = "Login", id = UrlParameter.Optional } // 參數默認值
            );
        }

        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();

            RegisterGlobalFilters(GlobalFilters.Filters);
            RegisterRoutes(RouteTable.Routes);
        }
    }
}

 注意：攔截器也可以寫在控制器類屬性上，寫在控制器類上表示攔截該控制器下所有action，如果寫在action只是攔截當前action有效

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace AttributeDemo.Controllers
{
    /// <summary>
    /// 測試Action攔截器
    /// </summary>
    [AttributeDemo.Common.ActionFilter(IsLogin = false)]
    public class ActionFilterTestController : Controller
    {
        //
        // GET: /ActionFilterTest/
    }
}