Sir i use triggers when i select something from dropdownlist then gridview should display.
here update panels are not nested.
1) firstly i use update panel when something write in textbox then data will display in another textboxes for example when student roll no i write in textbox the their data will show in another textboxes. Here update panel is working perfectly.
Here in first i use triggers
<Triggers>
<asp:AsyncPostBackTrigger ControlID="txtolcrno" EventName="TextChanged" />
</Triggers>
2) second update panel i use when i select something from dropdownlist then gridview will display otherwise not Here in gridview i use Jquery scrollable fixed header with gridview
and in second
<asp:UpdatePanel ID="UpdatePanel3" runat="server">
<ContentTemplate>
<asp:GridView ID="GridView2" runat="server" AutoGenerateColumns="False"
ShowFooter="True" Width="420px" DataKeyNames="Charge_id" CssClass="GridViewStyle" OnRowDeleting="GridView2_RowDeleting" >
<EditRowStyle CssClass="EditRowStyle" />
<HeaderStyle CssClass="HeaderStyle" />
<RowStyle CssClass="RowStyle" />
<AlternatingRowStyle CssClass="AltRowStyle" />
<Columns>
<asp:BoundField DataField="Charge_id" HeaderText="Charge_id">
<HeaderStyle CssClass="headerstylelist" />
<ItemStyle HorizontalAlign="Center" />
</asp:BoundField>
<asp:BoundField DataField="Charge_Desc" FooterText="Total" HeaderText="Charge Description" >
<HeaderStyle CssClass="headerstylelist" />
<ItemStyle HorizontalAlign="Center" />
</asp:BoundField>
<asp:TemplateField HeaderText="Unit Price" FooterStyle-Font-Bold="True">
<ItemTemplate>
<%# GetUnitPrice(decimal.Parse(Eval("OPD_Fees").ToString())).ToString("N2") %>
</ItemTemplate>
<FooterTemplate>
<asp:Label ID="Label1" runat="server" >
<%# GetTotal().ToString("N2") %> </asp:Label>
</FooterTemplate>
<FooterStyle Font-Bold="True" HorizontalAlign="Center" />
<HeaderStyle CssClass="headerstylelist" />
<ItemStyle HorizontalAlign="Center" />
</asp:TemplateField>
<asp:TemplateField HeaderText="Delete">
<ItemTemplate>
<span onclick="return confirm('Are you sure to Delete the Row?')">
<asp:ImageButton ID="imgbtnDelete" CommandName="Delete" Text="Delete"
runat="server" ImageUrl="~/Images/del1.png" ToolTip="Delete"
CausesValidation="False" /></span>
</ItemTemplate>
<HeaderStyle CssClass="headerstylelist" />
<ItemStyle HorizontalAlign="Center" />
</asp:TemplateField>
</Columns>
<HeaderStyle HorizontalAlign="Left" />
</asp:GridView>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="ddlfeestype" EventName="SelectedIndexChanged" />
</Triggers>
</asp:UpdatePanel>
