protected void UpdateTimeStamp(object sender, AjaxEventArgs e)
  {
    this.SetTime();
  }

//Html 调用上述方法
    <ext:Button ID="Button1" runat="server" Text="Click Me">
      <AjaxEvents>
        <Click OnEvent="UpdateTimeStamp">
          <EventMask ShowMask="true" MinDelay="500" Msg="Updating TimeStamp..."  />
        </Click>
      </AjaxEvents>
    </ext:Button>

OnEvent="UpdateTimeStamp" 就是指点击按钮后调用服务端方法UpdateTimeStamp 来更新某个标签的时间

<script runat="server">
  [AjaxMethod]
  public void SetTimeStamp()
  {
    this.Label1.Text = string.Concat("Server Time: ", DateTime.Now.ToLongTimeString());
  }
</script>

<ext:Button ID="Button5" runat="server" Text="Click Me" Icon="Lightning">
  <Listeners>
    <Click Handler="Coolite.AjaxMethods.SetTimeStamp();" />
  </Listeners>
</ext:Button>