MVC中的Action过滤器

Action过滤器可以用在调用动作方法之前或之后，执行一些特殊的逻辑，比如用登录验证：

Action过滤器实现IActionFilter接口，该接口有两个方法：

 public interface IActionFilter
    {
        void OnActionExecuted(ActionExecutedContext filterContext);
        void OnActionExecuting(ActionExecutingContext filterContext);
    }

我们先创建一个BaseController，在这个基类中重写OnActionExecuting方法，用于让其他的控制器继承此基类。如：

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Script.Serialization;
using XFK.PICCInsureTravel.Common;
using XinfuMall.XinfuWeb.PublicClass;

namespace XFK.PICCInsureTravel.Controllers
{
    public abstract class BaseController : Controller
    {
        public JavaScriptSerializer js = new JavaScriptSerializer();
        public LogHelper log = null;
        public UserSession user { get; set; }
        public EnterpriseAccountSession enterprise { get; set; }
        protected override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            base.OnActionExecuting(filterContext);
            LogHelper.WriteLog("进入BaseController");
            TempData["xinfuUrl"] = System.Configuration.ConfigurationManager.AppSettings["xinfuUrl"];
            if (XFK.Infrastructure.Util.SessionManager.Read(UserUtil.user_sessionStr) != null)
            {
                user = XFK.Infrastructure.Util.SessionManager.Read(UserUtil.user_sessionStr) as UserSession;
                object enterpriseId = XFK.Infrastructure.Util.SessionManager.Read(EnterpriseUtil.enterprise_sessionId);
                enterprise = new EnterpriseAccountSession();
                enterprise.Id = Convert.ToInt32(enterpriseId);
                ViewBag.UserName = user.AccountName;
                ViewBag.Enterpriseid = Convert.ToInt32(enterpriseId);
                var limitEnterprise = String.IsNullOrEmpty(ConfigurationManager.AppSettings["limitEnterprise"]) ? "" : ConfigurationManager.AppSettings["limitEnterprise"];
                if (limitEnterprise.Split(',').Contains(enterprise.Id.ToString()))
                {
                    System.Web.HttpContext.Current.Response.Write("对不起，所属的企业没有订购此产品的权限！");
                }
            }
            else
            {
                filterContext.Result = new RedirectResult(ConfigurationManager.AppSettings["xinfuUrl"] + "mall/Login?originUrl=" + HttpUtility.UrlEncode(Request.Url.ToString()));
                LogHelper.WriteLog("当前访问的路径是：" + ConfigurationManager.AppSettings["xinfuUrl"] + "mall/Login?originUrl=" + HttpUtility.UrlEncode(Request.Url.ToString()));
            }
        }
    }
}

注意，当验证不通过时，我们给filterContext.Result赋值，用于跳转页面。这个filterContext.Result属性是一个ActionResult类型的子集---RedirectResult：

当执行到filterContext.Result时，我们给它赋值以后，便会执行跳转。

这个BaseController建好以后，下面的工作就是在其他控制器中使用了：

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

namespace XFK.PICCInsureTravel.Controllers
{
    public class HomeController : BaseController
    {
        public ActionResult Index()
        {
            return View();
        }
    }
}

参考：http://skybirdzw.blog.163.com/blog/static/72570626201781465310313/