Dropdownlist of pager template not working properly

Hi,
I have taken a pager template inside gridview to implement paging functionality more efficiently. The issue is that, when I change the value from 1 to 2 from dropdownlist, it does not shows any result.
Please see the code and let me know where I am going wrong.
<asp:GridView ID="grdTeacherProfile" runat="server" Width="100%" border="1" Style="border: 1px solid #E5E5E5;" CellPadding="3" FooterStyle-BackColor="#e3e3e3" AutoGenerateColumns="false" AllowPaging="true" CssClass="hoverTable" DataKeyNames="Id" PageSize="2" ShowFooter="true" HeaderStyle-CssClass="k-grid td" OnDataBound="grdTeacherProfile_DataBound" OnPageIndexChanging="grdTeacherProfile_PageIndexChanging" OnRowDeleting="grdTeacherProfile_RowDeleting" ...