This article works fine but when I used dropdownlist with selectedindexchanged event inside panel in gridview not working after expand collapse.

Expand Collapse GridView using jQuery in ASP.Net with C# and VB.Net

<asp:TemplateField HeaderText="Commission">
    <ItemTemplate>  
        <img alt="" style="cursor: pointer" src="img/plus.png" /> 
        <asp:Panel ID="pnlOrders" runat="server"  style="display:none">
            <div class="mb-20">
            <div class="row">
            <label class="col-sm-2 col-lg-2 col-form-label">Select Bank</label>
            <div class="col-sm-4 col-lg-4">
            <div class="input-group">
            <asp:DropDownList ID="ddlbank" runat="server" CssClass="form-control" AutoPostBack="true" OnSelectedIndexChanged="ddlbank_SelectedIndexChanged"></asp:DropDownList>
            <asp:RequiredFieldValidator ID="re1" InitialValue="0" runat="server"  ControlToValidate="ddlbank" ValidationGroup="vu1" ErrorMessage="Select Bank" ForeColor="Red" Display="Dynamic" ></asp:RequiredFieldValidator>
            </div>
            </div>
            </div>
        </asp:Panel>
    </ItemTemplate>
</asp:TemplateField>