Thanks for ur reply.But it's not working my gridview code is
<asp:GridView ID="gvGroups" ShowHeader="False" runat="server" BackColor="White" BorderColor="#CCCCCC" BorderStyle="None" BorderWidth="1px" CellPadding="2" EnableViewState="False" AutoGenerateColumns="False" Width="100%">
<FooterStyle BackColor="White" ForeColor="#000066" />
<RowStyle ForeColor="#000066" Wrap="False" />
<SelectedRowStyle BackColor="#669999" Font-Bold="True" ForeColor="White" />
<PagerStyle BackColor="White" ForeColor="#000066" HorizontalAlign="Left" />
<HeaderStyle BackColor="#006699" Font-Bold="True" ForeColor="White" />
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="chk" runat="server" Width="4%" />
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="Addn_Class" HeaderStyle-Width="21%" ></asp:BoundField>
<asp:BoundField DataField="Addn_String" HeaderStyle-Width="24%" ></asp:BoundField>
<asp:BoundField DataField="Addn_Name" HeaderStyle-Width="49%" />
</Columns>
</asp:GridView></asp:Panel>
i am waiting for ur reply