今天大家共同学习下ASP.NET MVC2.0中自定义filters,这一节主要学习下ActionFilterAttribute，
ActionFilterAttribute继承IActionFilter, IResultFilter接口,并且继承FilterAttribute类.
ActionFilterAttribute可以监控action执行过程中所有阶段，包括日志，异常处理等功能.
主要包括以下四个重载方法
OnActionExecuting，OnActionExecuted，OnResultExecuting，OnResultExecuted
1.OnActionExecuting是在action开始前执行
用于身份验证和服务器端缓存输出
2. OnActionExecuted在action结束后执行
主要用于异常处理
3. OnResultExecuting在返回result前执行
主要用于设置客户端缓存和服务器端压缩
4. OnResultExecuted在返回result后执行
主要用于异常处理和页面尾部输出调试信息
以下两个DEMO，将展示actionfilter的具体用法
demo1:
在这个DEMO中我们将展示action在各个阶段的执行时间，并在页面中输出。
首先我们定义一个ActionLogAttribute类
- using System;
- using System.Collections.Generic;
- using System.Linq;
- using System.Web;
- using System.Web.Mvc;
- namespace MvcAppOne.ActionFilters
- {
- publicclass ActionLogAttribute : ActionFilterAttribute
- {
- /// <summary>
- /// 表示actionID
- /// </summary>
- publicint ID
- {
- get;
- set;
- }
- /// <summary>
- /// 在 action开始前执行
- /// </summary>
- /// <param name="filterContext"></param>
- publicoverridevoid OnActionExecuting(ActionExecutingContext filterContext)
- {
- filterContext.RequestContext.HttpContext.Response.Write(ID.ToString()+":actinon开始执行" + DateTime.Now.ToString() + "<br/>");
- base.OnActionExecuting(filterContext);
- }
- /// <summary>
- /// 在action结束后执行
- /// </summary>
- /// <param name="filterContext"></param>
- publicoverridevoid OnActionExecuted(ActionExecutedContext filterContext)
- {
- filterContext.RequestContext.HttpContext.Response.Write(ID.ToString()+":actinon执行结束" + DateTime.Now.ToString() + "<br/>");
- base.OnActionExecuted(filterContext);
- }
- /// <summary>
- /// 在result开始前执行
- /// </summary>
- /// <param name="filterContext"></param>
- publicoverridevoid OnResultExecuting(ResultExecutingContext filterContext)
- {
- filterContext.RequestContext.HttpContext.Response.Write(ID.ToString()+":result执行开始" + DateTime.Now.ToString() + "<br/>");
- base.OnResultExecuting(filterContext);
- }
- /// <summary>
- /// 在result结束后执行
- /// </summary>
- /// <param name="filterContext"></param>
- publicoverridevoid OnResultExecuted(ResultExecutedContext filterContext)
- {
- filterContext.RequestContext.HttpContext.Response.Write(ID.ToString()+":result执行结束" + DateTime.Now.ToString() + "<br/>");
- base.OnResultExecuted(filterContext);
- }
- }
- }
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.Mvc;namespace MvcAppOne.ActionFilters{ public class ActionLogAttribute : ActionFilterAttribute { /// /// 表示actionID /// public int ID { get; set; } /// /// 在 action开始前执行 /// /// public override void OnActionExecuting(ActionExecutingContext filterContext) { filterContext.RequestContext.HttpContext.Response.Write(ID.ToString()+":actinon开始执行" + DateTime.Now.ToString() + ""); base.OnActionExecuting(filterContext); } /// /// 在action结束后执行 /// /// public override void OnActionExecuted(ActionExecutedContext filterContext) { filterContext.RequestContext.HttpContext.Response.Write(ID.ToString()+":actinon执行结束" + DateTime.Now.ToString() + ""); base.OnActionExecuted(filterContext); } /// /// 在result开始前执行 /// /// public override void OnResultExecuting(ResultExecutingContext filterContext) { filterContext.RequestContext.HttpContext.Response.Write(ID.ToString()+":result执行开始" + DateTime.Now.ToString() + ""); base.OnResultExecuting(filterContext); } /// /// 在result结束后执行 /// /// public override void OnResultExecuted(ResultExecutedContext filterContext) { filterContext.RequestContext.HttpContext.Response.Write(ID.ToString()+":result执行结束" + DateTime.Now.ToString() + ""); base.OnResultExecuted(filterContext); } }} 然后我们建立一个VIEW页面，ShowNews页面
然后再建立一个ACTION，并把属性标记在action上面
- [ActionFilters.ActionLog(ID=3)]
- public ActionResult ShowNews()
- {
- return View();
- }
[ActionFilters.ActionLog(ID=3)] public ActionResult ShowNews() { return View(); } 此时我们运行ShowNews页面，我们将看到如下效果
demo2: 接着我们看第二个DEMO,在这个demo中，我们将展现actionFILTER中各个方法的作用
我们建一个类 ActionDealAttribute
- publicclass ActionDealAttribute : ActionFilterAttribute
- {
- publicoverridevoid OnActionExecuting(ActionExecutingContext filterContext)
- {
- //用户没有验证通过,转向登录页面
- if (!filterContext.RequestContext.HttpContext.User.Identity.IsAuthenticated)
- {
- filterContext.Result = new RedirectResult("../account/logon");
- }
- }
- publicoverridevoid OnActionExecuted(ActionExecutedContext filterContext)
- {
- //异常处理
- if (filterContext.Exception!=null)
- {
- filterContext.ExceptionHandled=true;
- filterContext.Result = new RedirectResult("../shared/Error");//转向错误页面
- }
- }
- publicoverridevoid OnResultExecuting(ResultExecutingContext filterContext)
- {
- base.OnResultExecuting(filterContext);
- }
- publicoverridevoid OnResultExecuted(ResultExecutedContext filterContext)
- {
- base.OnResultExecuted(filterContext);
- }
- }
public class ActionDealAttribute : ActionFilterAttribute { public override void OnActionExecuting(ActionExecutingContext filterContext) { //用户没有验证通过,转向登录页面 if (!filterContext.RequestContext.HttpContext.User.Identity.IsAuthenticated) { filterContext.Result = new RedirectResult("../account/logon"); } } public override void OnActionExecuted(ActionExecutedContext filterContext) { //异常处理 if (filterContext.Exception!=null) { filterContext.ExceptionHandled=true; filterContext.Result = new RedirectResult("../shared/Error");//转向错误页面 } } public override void OnResultExecuting(ResultExecutingContext filterContext) { base.OnResultExecuting(filterContext); } public override void OnResultExecuted(ResultExecutedContext filterContext) { base.OnResultExecuted(filterContext); } } 再建立一个news页面，并建立一个对应的action
如果访问news页面需要登录才能访问，就在news对应的action标记此属性，在OnActionExecuting中进行处理
- [ActionFilters.ActionDeal]
- public ActionResult News()
- {
- return View();
- }
[ActionFilters.ActionDeal] public ActionResult News() { return View(); } 如果news页面访问的时候出现异常，就会转向错误页面，在OnActionExecuted中进行处理
- [ActionFilters.ActionDeal]
- publicvoid News()
- {
- thrownew Exception();
- }
[ActionFilters.ActionDeal] public void News() { throw new Exception(); } 以上只是自定义action的简单用法，供大家参考。
代码下载: