I have installed AJAX for ASP.NET for use with DNN 4.8.2, but it seems that DNN won't recognize that I have it installed or enabled.  I updated the web.config in the proper places, and yet, it always thinks it's not installed or enabled.  In the IsEnabled() method in AJAX.vb in the DotNetNuke library:

   Public Shared Function IsEnabled() As Boolean
            If HttpContext.Current.Items("System.Web.UI.ScriptManager") Is Nothing Then
                Return False
            Else
                Return CType(HttpContext.Current.Items("System.Web.UI.ScriptManager"), Boolean)
            End If
        End Function

 HttpContext.Current.Items("System.Web.UI.ScriptManager") is always nothing.  Does anyone know exactly how this stuff works?

Also, in my debugging the source to figure out what's going on, the method ScriptManagerType() gets called a lot, which always seems to return false also.

Private Shared Function ScriptManagerType() As Type
            If m_ScriptManagerType Is Nothing Then
                If Not m_Initialized Then
                    m_ScriptManagerType = Reflection.CreateType("System.Web.UI.ScriptManager", True)
                End If
                m_Initialized = True
            End If
            Return m_ScriptManagerType
        End Function

 When I debug, even when I start from navigating to the DNN site, m_Initialized is already set to true and that it'll always be set to true, so m_ScriptManagerType never ever gets set.  The m_Initialized variable only seems to be used in ScriptManagerType(), so I can't think of anything else that would mess with that variable.  Is anyone running into problems having the AJAX class properly reporting whether AJAX is actually installed?  I've been tearing my hair out over this.

My main issue was that I was trying to include the DNN URLControl inside of an UpdatePanel.  It worked fine until I had to upload a file.  It appears that the file upload part won't work inside of an UP because it needs a full postback.

Originally, I didn't use the SupportsPartialRendering, and manually handled the ajax, but now it seems like that file upload will only work if I do use SupportsPartialRendering.  The only thing is, wherever I use it, that ajax progress bar shows up, and I don't necessarily want it showing up all the time.  When I use the partial rendering option in the module definitions, it works fine, with the exception of that progress bar I want to hide.  Is there a way to hide it?

The DNN URLControl does already register the file upload button as a postback control.  The problem is that it doesn't seem to work.  When you call RegisterPostbackControl within DNN, it calls the ScriptManagerType() method inside AJAX.vb:

 Private Shared Function ScriptManagerType() As Type
            If m_ScriptManagerType Is Nothing Then
                If Not m_Initialized Then
                     m_ScriptManagerType = Reflection.CreateType("System.Web.UI.ScriptManager", True)
                End If
                m_Initialized = True
            End If
            Return m_ScriptManagerType
        End Function.

The problem is that m_Initialized is always somehow set to True, so m_ScriptManagerType never gets set, so DNN doesn't add the necessary ScriptManager tag to enable ajax.  What I did was comment out  the m_Initialized check so it always assigns m_ScriptManagerType.  When I do this, the file upload button (the cmdSave button in the file control) will properly register, and the file uploader works.  It seems like a hack, but I don't know how else to get it working.  If anyone's reading this and needs a more detailed explanation of what I did and why, just ask, and I'll be happy to go into more detail.