Using AjaxControlToolkit in SharePoint: Multiple instances of ScriptManagers?

Question

I'm trying to use AjaxControlToolkit controls (specifically CalendarExtender and ComboBox), but am having problems with the ScriptManager control. I've got the ToolkitScriptManager at the top of the form, but when I load the page, I get this error:

Only one instance of a ScriptManager can be added to the page.

As soon as I removed the ScriptManager, I get this error:

Microsoft JScript runtime error: AjaxControlToolkit requires ASP.NET Ajax 4.0 scripts. Ensure the correct version of the scripts are referenced. If you are using an ASP.NET ScriptManager, switch to the ToolkitScriptManager in AjaxControlToolkit.dll.

I haven't added any other script managers anywhere else, and I've got the (.NET 3.5) DLL registered in GAC, and copies in the application's bin and _app_bin folders.

What's going on?

Answer 1

It's throwing the error because the <asp:ScriptManager> tag is most likely defined in your master page, causing two instances on the page you are trying to load.

http://social.msdn.microsoft.com/Forums/br/sharepoint2010general/thread/54c271ee-de71-4e47-b02b-29a1d540b81c