ASP.NET MVC ActionFilterAttribute的執行順序

http://diaosbook.com/Post/2014/6/3/execution-order-of-actionfilter-aspnet-mvc

ASP.NET MVC里面我們要自定義ActionFilter的時候會發現有4個方法可以override：OnActionExecuting，OnActionExecuted，OnResultExecuting，OnResultExecuted。他們分別在什么時候執行一直是困擾人類的一個問題。我代表人類做了一個簡單的實驗：

首先自定義一個ActionFilter，每個方法執行的時候都在VS的OUTPUT窗口輸出信息：

public class TestActionFilter : ActionFilterAttribute { public override void OnActionExecuting(ActionExecutingContext filterContext) { Debug.WriteLine("OnActionExecuting"); base.OnActionExecuting(filterContext); } public override void OnActionExecuted(ActionExecutedContext filterContext) { Debug.WriteLine("OnActionExecuted"); base.OnActionExecuted(filterContext); } public override void OnResultExecuting(ResultExecutingContext filterContext) { Debug.WriteLine("OnResultExecuting"); base.OnResultExecuting(filterContext); } public override void OnResultExecuted(ResultExecutedContext filterContext) { Debug.WriteLine("OnResultExecuted"); base.OnResultExecuted(filterContext); } }

Controller里為了搞清執行順序，也需要輸出：

[TestActionFilter] public ActionResult Index() { Debug.WriteLine("Before return View()"); return View(); }

最后是View：

@{ Debug.WriteLine("Hello from Index.cshtml"); }

執行結果是這樣的，有圖有JJ：

1. OnActionExecuting

2. Before return View()

3. OnActionExecuted

4. OnResultExecuting

5. Hello from Index.cshtml

6. OnResultExecuted