母版页中contentplaceholder之外的更新面板导致回发到内容页

Question

I have something like this in my Master Page:

    <asp:UpdatePanel ID="uppnlUtilities" runat="server" UpdateMode="Conditional">
    <Triggers>
        <asp:AsyncPostBackTrigger  ControlID="Timer1" EventName="Tick" />
    </Triggers>
    <ContentTemplate>
        <asp:Panel ID="pnlTopUtilities" runat="server">
            <asp:HyperLink ID="lnkCheckUpdates" runat="server" ImageUrl="~/images/viewupdates.gif" NavigateUrl="~/CheckUpdates.aspx" CssClass="imagelink"></asp:HyperLink>
            <asp:HyperLink ID="lnkAlertArchive" runat="server" ImageUrl="~/images/AlertArchives.gif" NavigateUrl="~/AlertArchive.aspx" 
                CssClass="imagelink" Visible="true"></asp:HyperLink>
            <asp:HyperLink ID="lnkNewAlert" runat="server" ImageUrl="~/images/AlertWaiting.gif" NavigateUrl="~/NewAlerts.aspx" 
                onclick="window.open (this.href, 'popupwindow', 'width=400,height=300,scrollbars,resizable'); return false;"
                CssClass="imagelink" Visible="false"></asp:HyperLink>
        </asp:Panel>
    </ContentTemplate>
</asp:UpdatePanel>
<asp:Timer ID="Timer1" runat="server" Interval="10000" OnTick="Timer1_Tick"></asp:Timer>

..........
.........
div id="divBody" class="group">
    <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
    </asp:ContentPlaceHolder>
</div>

I do see the partial post back within master page, but I also see the post back in content pages. When I put a break point on page_load, in content page, the code execution hits it. Any help is appreciated. Thanks!

Answer 1

The update panel does not change the postback. The page will go through its entire lifecycle. The difference an update panel makes is that the postback is asynchronous and only the content of the update panel is rendered.

Here is the relevant quote from MS Description of the UpdatePanel

When partial-page updates are enabled, controls can asynchronously post to the server. An asynchronous postback behaves like a regular postback in that the resulting server page executes the complete page and control life cycle. However, with an asynchronous postback, page updates are limited to regions of the page that are enclosed in UpdatePanel controls and that are marked to be updated. The server sends HTML markup for only the affected elements to the browser.