ASP.NET C# ajaxToolkit Updatepanel with Progress bar Syntax

<style>

.divWaiting {

            position: fixed;

            background-color: #FAFAFA;

            z-index: 2147483647 !important;

            opacity: 0.8;

            overflow: hidden;

            text-align: center;

            top: 0;

            left: 0;

            height: 100%;

            width: 100%;

            padding-top: 20%;

        }

</style>

 <asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">

    

    <asp:UpdatePanel runat="server" ID="upPopUps" UpdateMode="Always">

        <ContentTemplate>

 <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" AutoGenerateEditButton="True" OnRowCancelingEdit="GridView1_RowCancelingEdit" OnRowEditing="GridView1_RowEditing" OnRowUpdating="GridView1_RowUpdating" DataKeyNames="ID,MainID" OnRowDataBound="GridView1_RowDataBound" CssClass="table table-hover table-bordered table-responsive" AllowPaging="True" OnPageIndexChanging="GridView1_PageIndexChanging" PageSize="20" FirstPageText="First" PreviousPageText="Previous" NextPageText="Next" LastPageText="Last" AllowSorting="True" OnRowDeleting="GridView1_RowDeleting" OnInit="GridView1_Init" OnRowCommand="GridView1_RowCommand" OnSelectedIndexChanged="OnSelectedIndexChanged">

----------------

</asp:GridView>

 <asp:Panel runat="server" ID="pnlAddEdit" CssClass="modal-fade" Style="height: 80vh; overflow-y: auto;" BorderStyle="Double" Font-Size="Small">

</asp:Panel>

<asp:LinkButton ID="lnkFake" Text="" runat="server"></asp:LinkButton>

            <ajaxToolkit:ModalPopupExtender ID="popup" BehaviorID="popup" runat="server" DropShadow="false"

                PopupControlID="pnlAddEdit" TargetControlID="lnkFake" BackgroundCssClass="modalBackground" CancelControlID="btnPnlClose">

            </ajaxToolkit:ModalPopupExtender>

        

          </ContentTemplate>

        <Triggers>

            <%--<asp:PostBackTrigger ControlID="GridView1" />

            <asp:PostBackTrigger ControlID="btnPnlDelete" />

            <asp:PostBackTrigger ControlID="btnPnlUpdate" />--%>

        </Triggers>

    </asp:UpdatePanel>

        <asp:UpdateProgress ID="updprogress" runat="server" DisplayAfter="0" AssociatedUpdatePanelID="upPopUps">

                   <ProgressTemplate>

                    <div class="divWaiting">

                         

                            <asp:Label ID="lblWait" runat="server" Text=" Please wait... " />

                            <asp:Image ID="imgWait" runat="server" ImageUrl="~/Content/images/refresh.gif"    />

                        

                        </div>

                   </ProgressTemplate>

            </asp:UpdateProgress>

</asp:Content>

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Note: Also where you want no autopostback in page, than you have to add that controls inside update panel.   Also we can comment the triggers. It will work as asyncpost.

reference:- https://stackoverflow.com/questions/12191436/how-i-can-use-the-updateprogress-control-to-show-a-wait-symbol