<%@ Register Assembly="AsyncControls" Namespace="DelvingWare.AsyncControls" TagPrefix="dw" %>

<%@ Register Assembly="AsyncControls" Namespace="DelvingWare.AsyncControls.Utils" TagPrefix="dw" %>

<dw:AsyncTimer runat="server" ID="tmrMain" Interval="1000" OnTick="tmrMain_Tick" />

<p>
<dw:AsyncButton runat="server" ID="btStart" 
Text="Start Timer" 
CausesValidation="true" 
OnClick="btStart_Click" 
DisableDuringCallback="false" 
CssClass="greyButton"/>

<dw:AsyncButton runat="server" ID="btStop" 
Enabled="false" 
Text="Stop Timer" 
OnClick="btStop_Click" 
DisableDuringCallback="false" 
CssClass="greyButton"/>
</p>

Interval: <dw:AsyncTextBox runat="server" ID="txtInterval" 
Size="3" 
MaxLength="4"
EnableValidation="enabled" 
MultiValidate="Range|RequiredField"
ErrorMessageCssClass="errorMsg" 
ErrorMessage="Please enter a valid timer interval. 1000 - 5000 "
MinimumValue="1000" 
MaximumValue="5000"
Text="1000" />(ms)
<br/>
<dw:AsyncLinkButton runat="server" ID="lnkMain"
OnClick="lnkMain_Click"
CausesValidation="true"
Visible="false"
Text="Update Tick Interval" />

<dw:AsyncLabel runat="server" ID="lblMain" RenderMode="paragraph">Click "Start Timer" when ready.</dw:AsyncLabel>

using System;
using DelvingWare.AsyncControls;
...
protected void Page_Load( object sender, EventArgs e )
{
    // enable AsyncWindow use
    AsyncPage.Invocation.EnableAsyncTimer = true;
}

protected void tmrMain_Tick( object sender )
{        
    // update the AsyncLabel text
    lblMain.Text = "The current server time is: "+ DateTime.Now;
}

protected void btStop_Click( object sender, AsyncEventArgs ae )
{
    // enable, disable the AsyncButtons
    btStart.Enabled = true;
    btStop.Enabled = false;

    // hide the AsyncLinkButton
    lnkMain.Visible = false;

    // stop the AsyncTimer
    tmrMain.Stop();

    // update the AsyncLabel text
    lblMain.Text = "Click \"Start Timer\" when ready.";

    // select all the text within the AsyncTextBox
    txtInterval.SelectAll();

    // set the user input focus the the AsyncTextBox
    txtInterval.Focus();
}

protected void btStart_Click( object sender, AsyncEventArgs ae )
{
    // ensure the page passed validation
    if ( !AsyncPage.IsValid )
        return;

    // disable/enable the AsyncButtons
    btStart.Enabled = false;
    btStop.Enabled = true;

    // show the AsyncLinkButton
    lnkMain.Visible = true;

    // set the AsyncTimer tick interval based on the user input
    tmrMain.Interval = int.Parse(txtInterval.Text);
    
    // start the timer
    tmrMain.Start();

    // update the AsyncLabel text
    lblMain.Text = "Click \"Stop Timer\" when ready.";
}

protected void lnkMain_Click( object sender, AsyncEventArgs ae )
{
    if ( !txtInterval.IsValid )
        return;

    // update the AsyncLabel
    lblMain.Text = "Updated the tick interval to "+ txtInterval.Text +" (ms).";

    // update the interval
    tmrMain.Interval = int.Parse(txtInterval.Text);
}

Imports System
Imports DelvingWare.AsyncControls
...

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
    ' enable AsyncWindow use
    AsyncPage.Invocation.EnableAsyncTimer = true
End Sub

Protected Sub tmrMain_Tick(ByVal sender As Object)
    ' update the AsyncLabel text
    lblMain.Text = ("The current server time is: " + DateTime.Now)
End Sub

Protected Sub btStop_Click(ByVal sender As Object, ByVal ae As AsyncEventArgs)
    ' enable, disable the AsyncButtons
    btStart.Enabled = true
    btStop.Enabled = false
    ' hide the AsyncLinkButton
    lnkMain.Visible = false
    ' stop the AsyncTimer
    tmrMain.Stop
    ' update the AsyncLabel text
    lblMain.Text = "Click \""Start Timer\"" when ready."
    ' select all the text within the AsyncTextBox
    txtInterval.SelectAll
    ' set the user input focus the the AsyncTextBox
    txtInterval.Focus
End Sub

Protected Sub btStart_Click(ByVal sender As Object, ByVal ae As AsyncEventArgs)
    ' ensure the page passed validation
    If Not AsyncPage.IsValid Then
        Return
    End If
    ' disable/enable the AsyncButtons
    btStart.Enabled = false
    btStop.Enabled = true
    ' show the AsyncLinkButton
    lnkMain.Visible = true
    ' set the AsyncTimer tick interval based on the user input
    tmrMain.Interval = Integer.Parse(txtInterval.Text)
    ' start the timer
    tmrMain.Start
    ' update the AsyncLabel text
    lblMain.Text = "Click \""Stop Timer\"" when ready."
End Sub

Protected Sub lnkMain_Click(ByVal sender As Object, ByVal ae As AsyncEventArgs)
    If Not txtInterval.IsValid Then
        Return
    End If
    ' update the AsyncLabel
    lblMain.Text = ("Updated the tick interval to "  _
                + (txtInterval.Text + " (ms)."))
    ' update the interval
    tmrMain.Interval = Integer.Parse(txtInterval.Text)
End Sub