updatepanel in webpart

    protected override void CreateChildControls()
    {
        base.CreateChildControls();
        LinkButton goButton;
        goButton = new LinkButton();
        goButton.ID = "butGo";
        goButton.Text = "Go";
        goButton.Command += new CommandEventHandler(goButton_Command);
        goButton.Click += new EventHandler(goButton_Click);
        goButton.CausesValidation = false;
        Controls.Add(goButton);
        UpdatePanel updatePanel;
        updatePanel = new UpdatePanel();

        updatePanel.ID = "upUpdatePanel";
        updatePanel.UpdateMode = UpdatePanelUpdateMode.Conditional;
        updatePanel.ChildrenAsTriggers = false;
        AsyncPostBackTrigger t = new AsyncPostBackTrigger();
        t.EventName = "Command";
        t.ControlID = goButton.ID;
        updatePanel.Triggers.Add(t);
        Label lb = new Label();
        lb.ID = "DT";
        lb.Text = "Time";
        updatePanel.ContentTemplateContainer.Controls.Add(lb);
        Controls.Add(updatePanel);

    }
    private void goButton_Command(object sender, CommandEventArgs e)
    {
        Control ctl = sender as Control;
        UpdatePanel up = ctl.NamingContainer.FindControl("upUpdatePanel") as UpdatePanel;
        Label lbl = up.ContentTemplateContainer.FindControl("DT") as Label;
        lbl.Text = DateTime.Now.ToString();

    }