AJAX change in .NET 4: Sys.Services.AuthenticationService

I'm testing my existing apps in VS 2010, and ran into my first break. ASP.NET AJAX authentication support has changed.

Sys.Services.AuthenticationServ开发者_如何学JAVAice.set_defaultLogoutCompletedCallback(OnLogoutCompleted);

This no longer works. "Sys" is defined, but "Sys.Services" is an undefined object. Does anyone have a quick pointer to the replacement functionality?

EDITED TO ADD:

I've marked this as answered, based on the information that ASP.NET AJAX has changed, and that the client-side AJAX is now separated from the Visual Studio 2010 and .NET 4 distributions. In itself, this is not sufficient for a successful migration, though. Among other things, the current MS AJAX beta does not support the extender wizard in the ASP.NET designer. Also, I haven't found a way to compile successfully with control extenders added in previous releases of ASP.NET AJAX. It looks like AJAX migration will be a tough area for ASP.NET apps in VS 2010.

Around VS 2010 release time, I hope to see a community wiki for migration tips and techniques.

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If you're using Visual Studio 2010 Beta 2, it could be your script references. The Microsoft Ajax library is now released out-of-band with the .NET Framework, so script resources that were embedded in System.Web.Extensions have been removed.

You need to download the most recent library from http://ajax.codeplex.com or use the new Microsoft Ajax Content Delivery Network (CDN).

Here are some resources that should help you.

The Microsoft Ajax Library and Visual Studio Beta 2

Announcing the Microsoft AJAX CDN