Nested update panel causing parent update panel to refresh

Question

I think I've tried every combination possible with update panels and I just cant seem to get this to work. I've got an update panel like so:

<asp:UpdatePanel runat="server" ID="upParent" UpdateMode="Conditional" ChildrenAsTriggers="False">
        <ContentTemplate>

       Some content...
     <div style="width:100%;text-align:center;">
                    <asp:Label ID="lblMainMessage" runat="server"></asp:Label>
                    <asp:UpdateProgress AssociatedUpdatePanelID="upParent" ID="UpdateProgress7" runat="server" DisplayAfter="100" DynamicLayout="True" Visible="True">
                        <ProgressTemplate>
                             <div class="loader ui-widget-overlay">
                                            Loading data, please wait...<br/><img style="border-style:none;" src="../../Images/ajax-loader.gif" alt="loading" />
                             </div>
                        </ProgressTemplate>
                    </asp:UpdateProgress>
        </div>
        <div>
        <asp:UpdatePanel runat="server" ID="upChild" UpdateMode="Conditional" ChildrenAsTriggers="False">
 <ContentTemplate>
                <asp:Timer ID="timerChecklists" runat="server" OnTick="TimerChecklistsTick" Interval="10000"></asp:Timer>
                                               <asp:GridView ID="gvChecklists" runat="server"
                                AutoGenerateColumns="False" >
                                <Columns>
                                        <ItemTemplate>
                                     <asp:TemplateField HeaderText="Ques. Ans. Yes">
                                        <ItemTemplate>
                                            <asp:Label ID="lblQuestionsAnsweredYes" runat="server" ForeColor="Green"
                                                Text='<%# DataBinder.Eval(Container, "DataItem.QuestionYesAnswered") %>' 
                                                ToolTip="Questions answered Yes."></asp:Label>
                                        </ItemTemplate>
                                        <FooterStyle HorizontalAlign="Center" />
                                        <HeaderStyle HorizontalAlign="Center" />
                                        <ItemStyle HorizontalAlign="Center" />
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Ques. Ans. No">
                                        <ItemTemplate>
                                            <asp:Label ID="lblQuestionsAnsweredNo" runat="server" ForeColor="Red" 
                                                Text='<%# DataBinder.Eval(Container, "DataItem.QuestionNoAnswered") %>' 
                                                ToolTip="Questions answered No."></asp:Label>
                                        </ItemTemplate>
                                        <FooterStyle HorizontalAlign="Center" />
                                        <HeaderStyle HorizontalAlign="Center" />
                                        <ItemStyle HorizontalAlign="Center" />
                                    </asp:TemplateField>
                                    <asp:TemplateField HeaderText="Ques. Ans. N/A">
                                        <ItemTemplate>
                                            <asp:Label ID="lblQuestionsAnsweredNA" runat="server" ForeColor="Gray" 
                                                Text='<%# DataBinder.Eval(Container, "DataItem.QuestionNAAnswered") %>' 
                                                ToolTip="Questions answered N/A."></asp:Label>
                                        </ItemTemplate>
                                        <FooterStyle HorizontalAlign="Center" />
                                        <HeaderStyle HorizontalAlign="Center" />
                                        <ItemStyle HorizontalAlign="Center" />
                                    </asp:TemplateField>
                                </Columns>
                                </asp:GridView>  
                                <asp:Image ID="imgLoader" runat="server" ImageUrl="/Images/ajax-loader.gif" /> 
                                </td>
                                </tr>
                                </table>   
                                </div>          
                                <div style="width:100%;text-align:center;">
                                    <asp:Label ID="lblspChecklists2" runat="server"></asp:Label>
                                </div> 
             </ContentTemplate>
                 <Triggers>
                    <asp:PostBackTrigger ControlID="btnChecklistExcel"/>
                     <asp:AsyncPostBackTrigger ControlID="timerChecklists" />
                </Triggers>
             </asp:UpdatePanel>

What I am trying to accomplish is to sort of lazy load some gridview data due to its size. So what I simply did is wrap the gridview inside an update panel. I then place a timer within this update panel and set it to 10000 (10 seconds) for the tick event. I set the event OnTick as shown:

   protected void TimerChecklistsTick(object sender, EventArgs e)
        {
            LoadChecklistsSubPanel();
            timerChecklists.Enabled = false;
            imgLoader.Visible = false;
        }

The LoadChecklistsSubPanel simply gets a dataset and assigns it to the grid views datasource and does a databind. This all works fine...however my issue is the following:

Note as mentioned a parent update panel and a child update panel. Within this I have an Update progress associated to the update panel upParent. But my issue is when the 10 seconds hits and the timer event is fired this updateprogress is shown (in effect causing my entire page to basically load). I would think that this would not happen given the updatemode is condition and children as triggers is false.

I have also tried ChildrenAsTriggers=true, I've tried to make the update panel mode always, I've tried just about everything but my issue still persists. Right when 10 seconds hits the UpdateProgress (which shows a loading data, please wait overlay is displayed.

Other than that my grid view is getting binded correctly, its getting its data after 10 seconds, etc. My only issue is I cannot seem to understand why the UpdateProgress shows up and overlays my entire screen if all that is happening is my nested sub panel should be updating only.

Answer 1

The fact is that upPanel not updated, you can check this by putting a Label in the upPanel with value="0" and add lblTest.text +=1 under TimerChecklistsTick in codebehind. you can see that the value don't have any change.

In fact the problem is UpdateProgress control, UpdateProgress control is not a powerful tool and your expectations should not be very high.

if you want a powerful and customizable UpdateProgress you shoud make your own using JavaScript:

<script type="text/javascript">
    var postBackElement;
    var prm = Sys.WebForms.PageRequestManager.getInstance();
    prm.add_initializeRequest(InitializeRequest);
    prm.add_endRequest(EndRequest);
    function InitializeRequest(sender, args) {
        postBackElement = args.get_postBackElement();
        if (prm.get_isInAsyncPostBack()) {
            args.set_cancel(true);
        } else {
            //Put your progress UI here
            //Check Trigger Id if needed.
            //Show an image or Hide another div or ...
        }
    }
    function EndRequest(sender, args) {
    }
</script>

But Solution ...

But i was played a little with your code and found that if you remove your timer from inside UpdatePanels and put it outside them totally, your problem will be solved.

    </ContentTemplate>
</asp:UpdatePanel>
//Outside the upParent
<asp:Timer ID="timerChecklists" runat="server" OnTick="TimerChecklistsTick" Interval="10000"></asp:Timer>

The problem is persist for any control that placed inside child updatepanels. i don't know if there are a basis solution or not but as i say UpdateProgress is a simple and quick solution but not good in performance and flexibility totally.

Update This is simulated code what work for me (ASP.NET 4.5, Chrome 36):

<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="Default2.aspx.vb" Inherits="StackOverflowTests_WebVB.net.Default2" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
        <asp:UpdatePanel runat="server" ID="upParent" UpdateMode="Conditional" ChildrenAsTriggers="False">
            <ContentTemplate>
                <asp:Label ID="lbl1" runat="server" Text="0"></asp:Label>
                    <asp:UpdateProgress AssociatedUpdatePanelID="upParent" ID="UpdateProgress7" runat="server" DisplayAfter="100" DynamicLayout="True" Visible="True">
                        <ProgressTemplate>
                            <div class="loader ui-widget-overlay">
                                Loading data, please wait...<br />
                                <img style="border-style: none;" src="../Images/loading.gif" alt="loading" />
                            </div>
                        </ProgressTemplate>
                    </asp:UpdateProgress>
                <asp:UpdatePanel runat="server" ID="upChild" UpdateMode="Conditional" ChildrenAsTriggers="False">
                    <ContentTemplate>
                        <asp:Label ID="lbl2" runat="server" Text="0"></asp:Label>
                    </ContentTemplate>
                    <Triggers>
                        <asp:AsyncPostBackTrigger ControlID="timerChecklists" />
                    </Triggers>
                </asp:UpdatePanel>
            </ContentTemplate>
        </asp:UpdatePanel>
        <asp:Timer ID="timerChecklists" runat="server" OnTick="TimerChecklistsTick" Interval="1000"></asp:Timer>
    </div>
    </form>
</body>
</html>

CodeBehind:

Protected Sub TimerChecklistsTick(sender As Object, e As EventArgs)
    lbl1.Text += 1
    lbl2.Text += 1
End Sub

In output, lbl2 start counting without full postback and without showing the content of UpdateProgress on every Tick. If you move Timer inside the upChild, you can see that content of UpdateProgress will be shown on evey Tick, but still lbl1 show 0 without any change.