ModalPopupExtender OK Button click event not firing?

hi friend today i am goin to show you how to show Ajax modal popup extende
on asp.net butoon click in asp.net c#



ModalPopupExtender OK Button click event not firing?



1-->Take Acript manager  which is require for every ajax control(ajax extender)

 <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>

2--> Take one buton 
   <asp:LinkButton ID="LinkButton1"  runat="server"></asp:LinkButton>

3--> Take panel in which you show your popup content

 <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>

<asp:Panel ID="panel1" runat="server" BackColor="#cccccc">
                            <div style="padding:4px 4px 4px 4px;" >
                            <h3>Your Content Goes here</h3>
                            <img src="Img/2.jpg" />
                                </div>
                        </asp:Panel>
4--> Take one popup extender
    <cc1:ModalPopupExtender runat="server" PopupControlID="panel1" Enabled="True" TargetControlID="LinkButton1" ID="panel1_ModalPopupExtender"></cc1:ModalPopupExtender>
      
5-->Link bytton in which you click
 <asp:LinkButton ID="lnk_openpopup" OnClick="lnk_openpopup_Click" runat="server">Open Popup</asp:LinkButton>           

6-->
Code Behind


 protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                panel1_ModalPopupExtender.Hide();
            }
        }

        protected void lnk_openpopup_Click(object sender, EventArgs e)
        {
            panel1_ModalPopupExtender.Show();
        }



Thanks if you have any query and doubt and new quartion please let me know in comment section