Error in ScriptResource.axd: "Object of type 'Sys.Extended.UI.AccordionBehavior' cannot be converted to type 'Sys.UI.Behavior'

Question

I have an asp.net web site where I'm trying to resolve what looks like a problem with ASP.NET AJAX:

Microsoft JScript runtime error: Sys.ArgumentTypeException: Object of type 'Sys.Extended.UI.AccordionBehavior' cannot be converted to type 'Sys.UI.Behavior'. Parameter name: instance

I've googled around a lot, and looked at the code presented (see below, no idea what it means) but no luck.

I've tried changing scriptmanger scriptmode to release, and a bunch of other things too. Anyone have any ideas?

Details:

• Visual Studio 2010
• ASP.NET 4.0
• Ajax control toolkit 4.0
• jQuery 1.4.2
• jQuery UI 1.8.5

JS Code the error occurs in, inside ScriptResource.axd:

dispose:function()
{
var c=this;
b.UI.Behavior.callBaseMethod(c,eb); --------- this line 
var d=c._element;
if(d)
{
var f=c.get_name();
if(f)
d[f]=a;
var e=d._behaviors;
Array.remove(e,c);
if(!e.length)
d._behaviors=a;
delete c._element
}

}

Declaration of accordion control:

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="atlas" %>

(snip)

<atlas:Accordion ID="menu" runat="server" SelectedIndex="0"
    ContentCssClass="accordionContent" FadeTransitions="true" FramesPerSecond="30"
    TransitionDuration="250" AutoSize="None" Width="270">
</atlas:Accordion>

*Update: *
Added accordion control declaration as requested, is there anything else I can add that could be useful?

Does anyone have any idea about this error at all - am I right in thinking it's MS AJAX not playing nicely with other javascript (probably jQuery UI) on the page?

Answer 1

Are you using update panels on your page at all? If so, remember that once you add controls inside\outside of an update panel, the "scope" of objects included in a postback changes dramatically, as only objects wrapped within an UpdatePanel are included.

If this doesnt help, I apologize, but my experiences with ASP.NET AJAX have added a layer of complexity to the postback model with sites Ive implemented it on.