使用一个HttpModule拦截Http请求，来检测页面刷新(F5或正常的请求)

function newGuid() {
       var g = "";
       for (var i = 0; i < 32; i++) {
           g += Math.floor(Math.random() * 0xF).toString(0xF);
       }
       return g;
   }
    
   //gets a new guid and assigns its value to the hidden field
   function createPageIdentifier() {
       var guid = this.newGuid();
       document.getElementById(‘__REFRESH_FIELD‘).value = guid;
   }

private static Guid GetPageGuid(Page page)
           {
               string str = page.Request.Form["__REFRESH_FIELD"];
               return (!string.IsNullOrEmpty(str) ? new Guid(str) : Guid.Empty);
           }
    
           public void Init(HttpApplication application)
           {
               guids = new Queue(queueSize);
    
               application.PreRequestHandlerExecute += new EventHandler(RefreshModule.Application_PreRequestHandlerExecute);
           }
    
           private static void Page_Init(object sender, EventArgs e)
           {
               Page page = sender as Page;
               if (page != null)
               {
                   page.ClientScript.RegisterOnSubmitStatement(typeof(RefreshModule), "onsubmit", "createPageIdentifier();");
                   page.ClientScript.RegisterHiddenField("__REFRESH_FIELD", "");
    
                   HttpContext.Current.Items["IsRefreshed"] = false;
                   if (page.Request.HttpMethod == "POST")
                   {
                       Guid pageGuid = GetPageGuid(page);
                       bool flag = guids.Contains(pageGuid);
                       HttpContext.Current.Items["IsRefreshed"] = flag;
                       if (!flag && (pageGuid != Guid.Empty))
                       {
                           guids.Enqueue(pageGuid);
                           if (guids.Count > queueSize)
                           {
                               guids.Dequeue();
                           }
                       }
                   }
               }
           }