Label value does not change with ajax timer

Question

User-418973555 posted

having an ajax timer running to check connection, 

wondering why the label lblsessiontimeleft inside update panel udpSession does not change accordingly, meant for it to decrease its value by one second thereafter

protected void TimerSession_Tick(object sender, EventArgs e)
  {
    recheckconn();

    if ((string)Session["sConnLetter"] == "c")
    {
     
      DateTime datetimenow = DateTime.Now;
      DateTime datetimesession;
      datetimesession = datetimenow.AddMilliseconds((int)Session["sSessionTimeout"]);

      TimeSpan tstd;
      TimeSpan tstd1;

      tstd = datetimesession.AddMilliseconds((int)Session["sSessionTimeout"]) - DateTime.Now;
      tstd1 = tstd.Subtract(new TimeSpan(0, 0, 1));

      if (Session["sSessionTimeout1"] != null)
      {
        Session["sTimeDifferent"] = datetimesession.AddMilliseconds((int)Session["sSessionTimeout1"]) - DateTime.Now;
        tstd = datetimesession.AddMilliseconds((int)Session["sSessionTimeout1"]) - DateTime.Now;
        tstd1 = tstd.Subtract(new TimeSpan(0, 0, 1));
      }

      Session["sSessionTimeout1"] = tstd1.Milliseconds;

      lblsessiontimeleft.Text = tstd1.Milliseconds.ToString();

      pnlSession.Style.Add("display", "block");
      udpSession.Update();

    }

Answer 1

User839733648 posted

Hi 

According to your code, I've made a test on my side.

Since I'm not clear about the session's value. I've customized it.

And I do reprodcue your issue, the label's text will always the value without changing,

I've made debug and find that the request is sent every second.

But when I add the Thread.Sleep() method to affect DateTime.Now, the value will change.

The reason for the value not change may be the logic of your code.

Your calculation is about the datetime, the logic may result in the vlaue not changing. Please check that.

Here is my testing code.

            <asp:ScriptManager ID="ScriptManager1" runat="server" ></asp:ScriptManager>
            <asp:Timer ID="Timer1" runat="server" OnTick="Timer1_Tick" Interval="1000"></asp:Timer>
            <asp:UpdatePanel ID="UpdatePanel1" runat="server">
                <ContentTemplate>
                    <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
                </ContentTemplate>
                <Triggers>
                    <asp:AsyncPostBackTrigger ControlID="Timer1"/>
                </Triggers>
            </asp:UpdatePanel>

        protected void Timer1_Tick(object sender, EventArgs e)
        {
            Session["sSessionTimeout"] = 1;
            Session["sSessionTimeout1"] = 2;
            DateTime datetimenow = DateTime.Now;
            DateTime datetimesession;
            datetimesession = datetimenow.AddMilliseconds((int)Session["sSessionTimeout"]);
            Thread.Sleep(new Random().Next(3000));
            TimeSpan tstd;
            TimeSpan tstd1;

            tstd = datetimesession.AddMilliseconds((int)Session["sSessionTimeout"]) - DateTime.Now;
            tstd1 = tstd.Subtract(new TimeSpan(0, 0, 1));

            if (Session["sSessionTimeout1"] != null)
            {
                Session["sTimeDifferent"] = datetimesession.AddMilliseconds((int)Session["sSessionTimeout1"]) - DateTime.Now;
                tstd = datetimesession.AddMilliseconds((int)Session["sSessionTimeout1"]) - DateTime.Now;
                tstd1 = tstd.Subtract(new TimeSpan(0, 0, 1));
            }

            Session["sSessionTimeout1"] = tstd1.Milliseconds;
            var str = tstd1.Milliseconds.ToString(); 
            Label1.Text = tstd1.Milliseconds.ToString();
        }

Best Regards,

Jenifer

Answer 2

User-418973555 posted

made some modifications, 

 protected void Page_Load(object sender, EventArgs e)
  {
   
    Response.Cache.SetCacheability(HttpCacheability.NoCache);
    if (!IsPostBack)
    {
      lblErrMsg.Text = String.Empty;
      txtProductName.Text = String.Empty;
      txtProductDetail.Text = String.Empty;

      Session["Reset"] = true;
      Configuration config = WebConfigurationManager.OpenWebConfiguration("~/Web.Config");
      SessionStateSection section = (SessionStateSection)config.GetSection("system.web/sessionState");
      // timeout in miliseconds
      double timeout = (double)section.Timeout.TotalMinutes * 1000 * 60;
      //ClientScript.RegisterStartupScript(this.GetType(), "SessionAlert", "SessionExpireAlert(" + timeout + ");", true);
      Session["sSessionTimeout"] = timeout;

      if ((bool)Session["Reset"] == true)
      {
        Session["sSessionTimeout"] = timeout;
        Session["sSessionTimeout1"] = null;
      }

    }

  }

...


protected void TimerSession_Tick(object sender, EventArgs e)
  {
   
    if ((string)Session["sConnLetter"] == "c")
    {
     
      DateTime datetimenow = DateTime.Now;
      TimeSpan tstd;
      TimeSpan tstd1;

      if (Session["sSessionTimeout1"] != null)
      {
        Session["sTimeDifferent"] = datetimenow.AddMilliseconds((double)Session["sSessionTimeout1"]) - DateTime.Now;
        tstd = datetimenow.AddMilliseconds((double)Session["sSessionTimeout1"]) - DateTime.Now;
        tstd1 = tstd.Subtract(new TimeSpan(0, 0, 1));

        Session["sSessionTimeout1"] = tstd1.TotalMilliseconds;
      }
      else
      {
        tstd = datetimenow.AddMilliseconds((double)Session["sSessionTimeout"]) - DateTime.Now;
        tstd1 = tstd.Subtract(new TimeSpan(0, 0, 1));
        Session["sSessionTimeout1"] = tstd1.TotalMilliseconds;
      }

      lblsessiontimeleft.Text = tstd1.Hours.ToString() + ":" + tstd1.Minutes.ToString() + ":" + tstd1.Seconds.ToString();

      pnlSession.Style.Add("display", "block");
      udpSession.Update();

    }

    if ((string)Session["sConnLetter"] == "n")
    {

      pnlSession.Style.Add("display", "none");
      udpSession.Update();

      
    }

    
  }

Answer 3

User839733648 posted

Hi larnvok09,

According to your code, I'm not clear about your issue.

There occurs some error message when I try the code because of code lost.

If possible, please provide more details about your issue like the complete code including the front code and behind code,

also hope that you could describe your issue about your modified codes,  this will be easier for us to help with you.

Best Regards,

Jenifer