使用Filter跟踪Asp.net MVC页面加载（转）

public class TrackPageLoadPerformanceAttribute : ActionFilterAttribute
   {

      //这里使用log4net来打印出结果
       private static readonly ILog Log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

      //创建字典来记录开始时间，key是访问的线程Id.
       private readonly Dictionary _start = new Dictionary();

      //创建字典来记录当前访问的页面Url.
       private readonly Dictionary _url = new Dictionary();

       public override void OnActionExecuting(ActionExecutingContext filterContext)
       {
           //过滤掉ChildAction, 因为ChildAction实际上不是一个单独的页面
           if(filterContext.IsChildAction) return;

           var currentThreadId = System.Threading.Thread.CurrentThread.ManagedThreadId;

           try
           {
               _start.Add(currentThreadId, DateTime.Now);
               _url.Add(currentThreadId, filterContext.HttpContext.Request.Url == null
                   ? string.Empty
                   : filterContext.HttpContext.Request.Url.AbsoluteUri);
           }
           catch (Exception ex)
           {
               Log.Error(ex.ToString());
           }
       }

       public override void OnResultExecuted(ResultExecutedContext filterContext)
       {
           var currentThreadId = System.Threading.Thread.CurrentThread.ManagedThreadId;
           if (!_start.ContainsKey(currentThreadId)) return;

           try
           {

                //计算出当前页面访问耗时
               var costSeconds = (DateTime.Now - _start[currentThreadId]).TotalSeconds;
               if (costSeconds > 2)//如果耗时超过2秒，就是用log4net打印出，具体是哪个页面访问超过了2秒，具体使用了多长时间。
               {
                   Log.Info(string.Format("Access the action more than 2 seconds. cost seconds {1}.  URL: {0}", _url[currentThreadId], costSeconds));
               }
           }
           catch (Exception ex)
           {
               Log.Error(ex.ToString());
           }
           finally
           {
               _start.Remove(currentThreadId);
               _url.Remove(currentThreadId);
           }
       }
   }