ASP.NET Timer Event - asp.net

Question

protected void SubmitButtonClicked(object sender, EventArgs e)
{
System.Timers.Timer timer = new System.Timers.Timer();
---
---
//line 1
get_datasource();
String message = "submitted.";
ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "popupAlert", "popupAlert(' " + message + " ');", true);
timer.Interval = 30000;
timer.Elapsed += new ElapsedEventHandler(timer_tick);
// Only raise the event the first time Interval elapses.
timer.AutoReset = false;
timer.Enabled = true;
}
protected void timer_tick(object sender, EventArgs e)
{
//line 2
get_datasource();
GridView2.DataBind();
}
The problem is with the data in the grid view that is being displayed... since when get_datasource which is after line 1 is called the updated data is displayed in the grid view since it is a postback event but when the timer event handler is calling the timer_tick event the get_datasource function is called but after that the updated data is not visible in the grid view. It is nnot getting updated since the timer_tick is not a post back event

Answer 1

The server-side timer as you have implemented it, will not work for what you are trying to achieve.
If you wrap both the timer and gridview in a updatepanel, the timer will trigger a postback everytime the tick event fires and you be able to update the data.
Heres a great blog post to get you going: http://mattberseth.com/blog/2007/08/using_the_ajax_timer_control_a.html
<asp:UpdatePanel runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:GridView ID="GridView2" runat="server">
</asp:GridView>
<asp:Timer id="Timer1" runat="server" Interval="30000" OnTick="Timer_Tick" Enabled="false" />
<asp:Button ID="Button1" runat="server" Text="Update" OnClick="SubmitButtonClicked" />
</ContentTemplate>
</asp:UpdatePanel>
Server-side code:
private void Timer_Tick(object sender, EventArgs args)
{
get_datasource();
GridView2.DataBind();
Timer1.Enabled = false;
}
protected void SubmitButtonClicked(object sender, EventArgs e)
{
String message = "submitted.";
ScriptManager.RegisterStartupScript(this.Page, this.GetType(), "popupAlert", "popupAlert(' " + message + " ');", true);
get_datasource();
GridView2.DataBind();
Timer1.Enabled = true;
}

Answer 2

You cannot use a timer like that. While ASP.NET tries to hide the request/response cycle of HTTP, the cycle is still there so you cannot just do whatever you like in your postback: you still need to understand that a HTML response is being sent back in response to a HTTP request.
Is there any particular reason why you're trying to use a timer like this? It doesn't seem to make sense to me. What is it that you're trying to achieve?