ASP.NET AJAX suppress onbeforeunload for AJAX requests from updatepanel

Question

I am hooking the window.onbeforeunload event in an aspx page. I need that not to fire if I page a GridView that's in an UpdatePanel on the same page.

I have tried hooking the PageRequestManager's initializeRequest event but this fires too late, i.e. after onbeforeunload. I have also tried checking PageRequestManager.get_isInAsyncPostBack() in my onbeforeunload handler but that returns false too, gah!

I have read this SO thread :

537702

But that doesn't make sense to me other than GridView page links cause an unload whereas buttons in a GridView column do not? Anybody know how to solve this? I'm guessing only way is to attach client-side click handler to all the GridView's page anchors to set some boolean flag, but I'm not sure how to accomplish that in a reliable manner.

Answer 1

Ok JQuery to the rescue!

<script type="text/javascript">
    var flag = true;
    window.onbeforeunload = beforeUnloading;
    var prm = Sys.WebForms.PageRequestManager.getInstance();
    prm.add_pageLoaded(initPagers);

    function initPagers() {
        $(".gridViewPagerStyle").click(function() { flag = false; });
    }

    function beforeUnloading(){
        if(flag)
            return "unloading";

        flag = true;
    }
</script>

:
:   

<asp:GridView ... PagerStyle-CssClass="gridViewPagerStyle" ... />

:
:

Set a Css class for all pager links, use that to append javascript click handlers that set a flag when clicked, use flag to avoid onbeforeunload