Sys.WebForms.PageRequestManager is null or not an object

9 posts, 0 answers
  1. Joey
    Joey avatar
    32 posts
    Member since:
    Feb 2008

    Posted 06 May 2008 Link to this post

    I just upgraded my web site to version 2008.1415 of RadControls for ASP.Net Ajax and now i'm getting the error "Sys.WebForms.PageRequestManager is null or not an object". I'm running the web site via the ASP.Net Development Server not through IIS.

    I've done the following to try to resolve.

    • Un/Re-Installed ASP.Net Ajax 1.0.
    • Upgraded to the 1.0.20229.20821 (2-29-2008) version of AjaxControlToolkit.dll
    • Verified my web.config file was setup correctly via
    • Verified I had no xhtmlConformance element defined in the web.config
    • Used Fiddler to verify the .axd files are being downloaded correctly. All requests repsond with a 200 status code.

    What's else should I look at?

  2. Todd Anglin
    Todd Anglin avatar
    2040 posts
    Member since:
    Aug 2005

    Posted 06 May 2008 Link to this post


    It sounds like you know your way around an ASP.NET AJAX website, so I'll try to keep this brief. You didn't mention explicitly that you've got the necessary ScriptManager on your ASP.NET AJAX page, but I am going to assume that's a given.

    For reference, what version of the RadControls are you upgrading from? Another version of the Prometheus controls? If so, I assume the site worked fine before the upgrade and no other code changes have been made.

    Beyond that, you may want to check some of the general ASP.NET AJAX help out there for this type of error message. It's not specifically related to the RadControls, so you may find your answer there. Check out these resources to get started:

    Hope this helps-
  3. Joey
    Joey avatar
    32 posts
    Member since:
    Feb 2008

    Posted 07 May 2008 Link to this post

    Thanks Todd, I'm upgrading from version which is Q3 2007 and the site did work before the upgrade. After googling myself near to death I decided to just remove the existing ScriptManager from my master page and re-add it by hand and bam it starts working again! I compared the ScriptManager I originally had with the one I just added and there isn't a difference!!! Clearly there is a problem with one or more of Microsoft's technologies. I'm going to assume that there is a caching issue with either the temporary folder MS uses to dynamically compile .Net apps or the ASP.Net Development Server itself. If anyone knows how to clear this temporary .Net directory let me know.

    thx, joey
  4. Todd Anglin
    Todd Anglin avatar
    2040 posts
    Member since:
    Aug 2005

    Posted 07 May 2008 Link to this post


    Glad you solved your problem! I continue to insist that computers (and code) literally make crazy people seem sane (in other words, you really can repeat the same behavior and expect different results).

    For future reference, you can easily clear your Temporary ASP.NET files by deleting everything is the following directory:

    C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files

    Believe it or not, this true for both .NET 2.0 and .NET 3.x web sites. That should reveal how similar those frameworks really are- MS didn't even change the temp cache location! In any event, deleting those files is always a good idea if you're having weird problems.

    Good luck on the rest of your project.

  5. Bobby Davis
    Bobby Davis avatar
    5 posts
    Member since:
    Dec 2003

    Posted 03 Sep 2008 Link to this post

    This is actually not a Microsoft bug.  It is a Telerik bug.  You have to clear out the temp files because Telerik is not doing it.

    This behavior is very rare with Microsoft controls but with Telerik controls it is common place.
  6. Nicolaï
    Nicolaï avatar
    160 posts
    Member since:
    Apr 2008

    Posted 04 Feb 2009 Link to this post

    Hi ,

    I've tried everything and I'm still getting errors...
    After deleting everything in C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files
    and repasting huge web.config sections from
    I now get a javascript alert with "Sys.WebForms.PageRequestMana... An unknown error occured.. status code 500",
    instead of the little javascript error icon in ie7...

    I am using 2008.3.1314.20 of Telerik controls..
    The error only appears on a quite simple page and only after the second ajax request. It's extremely frustrating, because other pages with hierarchy grids, edit templates with radeditors, datepickers, datasources with some big sql commands seem to work flawlessly in the same webapp....
    After all the editing, I've lost track of the changes... I'm losing it..!

    If I hang myself, I might add a note "Telerik and Microsoft made me do it!" ..! *lol*

  7. Sebastian
    Sebastian avatar
    9934 posts

    Posted 04 Feb 2009 Link to this post

    Hello Nicolai,

    I am sorry to hear that you are having hard time addressing the error you receive. Unfortunately the reasons for it may vary and I am not able to provide a definite answer/solution for your case. However, the resources pointed below can help you troubleshoot and address it:

    Kind regards,
    the Telerik team

    Check out Telerik Trainer, the state of the art learning tool for Telerik products.
  8. Chris Marisic
    Chris Marisic avatar
    30 posts
    Member since:
    Sep 2009

    Posted 11 Sep 2009 Link to this post

    I had issues with this but I had the xhtmlConformance="Legacy" tag, when I replaced it with Transitional that fixed all of my problems!
  9. Tom
    Tom avatar
    44 posts
    Member since:
    Jun 2007

    Posted 29 Sep 2009 Link to this post

    I came across the same error, and thought I'd try the simple fix by Chris first - swap xhtmlConformance="Legacy" to "Transitional" in web.config and it worked for me too. Thanks Chris. 
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