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MVC源码分析 - Action/Result 过滤器(续)
上一篇 看到了Action/Result过滤器的执行顺序:
OnActionExecuting -> Action -> OnActionExecuted -> OnResultExecuting -> View-> OnResultExecuted
这一篇就来做几个例子吧.
一、Demo
上一篇 的代码可能并不怎么好懂. 首先, 我能在FilterConfig中注册过滤器, 可以在Controller中重写Action/Result过滤器或者是在Controller上标注过滤器特性, 还可以在方法上加上过滤器特性. 那么这些过滤器的执行, 都是在上一篇中的方法中执行的. 上一篇中, 并不能直观的看到这些顺序, 也是不好理解的点之一了.
但是上一篇提到过, 在调换顺序之后, 最先执行的应该是Controller里面的过滤器, 那么到底是不是这样呢?来看一下吧.
首先建几个过滤器, 都继承自 ActionFilterAttribute 类, 这里面有Action/Result的四个过滤器方法
//FilterConfig中注册使用 public class MyFilterConfigAttribute : ActionFilterAttribute { public override void OnActionExecuted(ActionExecutedContext filterContext) { filterContext.HttpContext.Response.Write("FilterConfigAttribute - OnActionExecuted<br />"); } public override void OnActionExecuting(ActionExecutingContext filterContext) { filterContext.HttpContext.Response.Write("FilterConfigAttribute - OnActionExecuting<br />"); } public override void OnResultExecuted(ResultExecutedContext filterContext) { filterContext.HttpContext.Response.Write("FilterConfigAttribute - OnActionExecuted<br />"); } public override void OnResultExecuting(ResultExecutingContext filterContext) { filterContext.HttpContext.Response.Write("FilterConfigAttribute - OnActionExecuting<br />"); } } //Controller上标注此特性 public class MyControllerAttribute : ActionFilterAttribute { public override void OnActionExecuted(ActionExecutedContext filterContext) { filterContext.HttpContext.Response.Write("ControllerAttribute - OnActionExecuted<br />"); } public override void OnActionExecuting(ActionExecutingContext filterContext) { filterContext.HttpContext.Response.Write("ControllerAttribute - OnActionExecuting<br />"); } public override void OnResultExecuted(ResultExecutedContext filterContext) { filterContext.HttpContext.Response.Write("ControllerAttribute - OnActionExecuted<br />"); } public override void OnResultExecuting(ResultExecutingContext filterContext) { filterContext.HttpContext.Response.Write("ControllerAttribute - OnActionExecuting<br />"); } } //Action上标注此特性 public class MyActionAttribute : ActionFilterAttribute { public override void OnActionExecuted(ActionExecutedContext filterContext) { filterContext.HttpContext.Response.Write("ActionAttribute - OnActionExecuted<br />"); } public override void OnActionExecuting(ActionExecutingContext filterContext) { filterContext.HttpContext.Response.Write("ActionAttribute - OnActionExecuting<br />"); } public override void OnResultExecuted(ResultExecutedContext filterContext) { filterContext.HttpContext.Response.Write("ActionAttribute - OnActionExecuted<br />"); } public override void OnResultExecuting(ResultExecutingContext filterContext) { filterContext.HttpContext.Response.Write("ActionAttribute - OnActionExecuting<br />"); } }
然后就是在控制器和视图.
[MyController] public class FootController : Controller { protected override void OnActionExecuted(ActionExecutedContext filterContext) { filterContext.HttpContext.Response.Write("FootController - OnActionExecuted<br />"); } protected override void OnActionExecuting(ActionExecutingContext filterContext) { filterContext.HttpContext.Response.Write("FootController - OnActionExecuting<br />"); } protected override void OnResultExecuted(ResultExecutedContext filterContext) { filterContext.HttpContext.Response.Write("FootController - OnResultExecuted<br />"); } protected override void OnResultExecuting(ResultExecutingContext filterContext) { filterContext.HttpContext.Response.Write("FootController - OnResultExecuting<br />"); } [MyAction] public ActionResult Get() { Response.Write("<br /><br />Action 方法被执行<br /><br />"); return View(); } }
@{ ViewBag.Title = "Get"; } <br /> <br /> Get - View视图被解析 <br /> <br />
准备妥当了, 上结果:
从以上结果中可以看出, 最先执行的, 是Controller里面的ActionExecuting方法.
这里的执行顺序, 有点类似递归的执行过程. 从这个结果来看上一篇的执行过程, 就很清晰了.
Controller内部Action/Result过滤器 - > FilterConfig注册Action/Result过滤器 - > Controller标注Action/Result特性 - > Action标注Action/Result特性
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MVC源码分析 - Action/Result 过滤器(续)