子控件UpdatePanel导致完全回发

Question

I'm trying to extract an UpdatePanel out to a child UserControl, so that I can use it multiple times in the same page. However, when I call __doPostback on the child control from the main page (at the end of page load - a couple of other things need to be obtained before data can be loaded), it refreshes the entire page, causing an infinite loop.

What really drives me up the wall, though, is that when the exact same UpdatePanel is embedded into the main page instead of being in a child control, partial postback works! I'm hoping someone has an idea why.

MainPage.ascx:

<%@ Register TagPrefix="test" TagName="GridControl" Src="~/Controls/GridControl.ascx" %>

<asp:ScriptManager ID="SM" runat="server" EnablePageMethods="true">

<test:GridViewControl ID="child" runat="server" />

<asp:UpdatePanel ID="embedded" runat="server" UpdateMode="Conditional">
    <ContentTemplate>
        <asp:GridView runat="server" AllowPaging="true" OnPageIndexChanging="gridView_PageIndexChanging">
            <Columns>
                ...
            </Columns>
        </asp:GridView>
    </ContentTemplate>
</asp:UpdatePanel>

MainPage.js:

pageLoad = function ()
{
    // Works great: no infinite loop, GridView paging works, embedded.Visible=false hides the grid
    __doPostBack("<%= embedded.ClientID %>");   

    // All of the problems
    $("#grid").update();                        
}
pageLoad(); 

ChildControl.ascx:

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="GridControl.ascx.cs" Inherits="Control" %>
<script type="text/javascript">
    var upClientID = "<%= updatePanel.ClientID %>";

    // Trigger the post-back so that the update panel re-loads data. 
    $.fn.update = function ()
    {
        __doPostBack(upClientID);
    };
</script>

<!-- Exactly the same as the embedded UpdatePanel -->
<asp:UpdatePanel ID="updatePanel" runat="server" UpdateMode="Conditional">
    <ContentTemplate>
        <asp:GridView ID="gridView"runat="server" AllowPaging="true" OnPageIndexChanging="gridView_PageIndexChanging">
            <Columns>
                ...
            </Columns>
        </asp:GridView>
    </ContentTemplate>
</asp:UpdatePanel>

I'm actually running into quite a number of problems with this child control - setting the Visible property doesn't do anything, GridView paging doesn't work... it surprises me that creating a simple child control should be so difficult.

Answer 1

(Answering my own question)

Not a fix for the issue exactly, but I eventually embedded the UpdatePanel into the main page and extracted the GridView as a child control. There was still some duplicate code, but postback began working out okay.