Value cannot be null or empty. Parameter name: handler

Thread is closed for posting
41 posts, 0 answers
  1. Iana Tsolova
    Admin
    Iana Tsolova avatar
    3388 posts

    Posted 20 Nov 2009 Link to this post

    Hello Dana,

    I am afraid that the mentioned error it not due to a bug in RadAjax and I am sure there is a certain reason for it to appear. If you could provide a sample project of your scenario which illustrates he problem, we would gladly debug it locally to find the exact cause of it and thus give you the best resolution. Otherwise it would be hard to guess what could have gone wrong in your case.

    Best wishes,
    Iana
    the Telerik team

    Instantly find answers to your questions on the new Telerik Support Portal.
    Watch a video on how to optimize your support resource searches and check out more tips on the blogs.
  2. Patrick Maeschli
    Patrick Maeschli avatar
    11 posts
    Member since:
    Jan 2008

    Posted 26 Jan 2010 Link to this post

    Hello..

    We are using the telerik treeview in our project, and have the same error occassionally in this project.

    Value cannot be null or empty.

    Parameter name: handler   at System.Web.UI.ScriptComponentDescriptor.AddEvent(String name, String handler)

       at Telerik.Web.ScriptObjectBuilder.DescribeComponent(Object instance, ScriptComponentDescriptor descriptor, IUrlResolutionService urlResolver, IControlResolver controlResolver)

       at Telerik.Web.UI.ControlItemContainer.DescribeComponent(ScriptComponentDescriptor descriptor)

       at Telerik.Web.UI.RadTreeView.DescribeComponent(ScriptComponentDescriptor descriptor)

       at Telerik.Web.UI.ScriptRegistrar.GetScriptDescriptors(Control control)

       at Telerik.Web.UI.RadDataBoundControl.GetScriptDescriptors()

       at System.Web.UI.ScriptControlManager.RegisterScriptDescriptors(IScriptControl scriptControl)

       at Telerik.Web.UI.RadDataBoundControl.RegisterScriptDescriptors()

       at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)

       at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)

       at System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer)

       at System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output)

       at System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer)

       at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)

       at System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer)

       at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)

       at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)

       at Microsoft.SharePoint.WebControls.UnsecuredLayoutsPageBase.RenderChildren(HtmlTextWriter writer)

       at System.Web.UI.Page.Render(HtmlTextWriter writer)

       at Microsoft.SharePoint.WebControls.UnsecuredLayoutsPageBase.Render(HtmlTextWriter writer)

       at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

    Troubleshoot issues with Windows SharePoint Services.

    Any News on this Subject?

    Thanks in Advance
    patrick

  3. Iana Tsolova
    Admin
    Iana Tsolova avatar
    3388 posts

    Posted 29 Jan 2010 Link to this post

    Hello Patrick,

    Could you please send us a sample replicating the mentioned error? As I am afraid that it would be hard to determine what could be the source of it based on the provided information.

    All the best,
    Iana
    the Telerik team

    Instantly find answers to your questions on the new Telerik Support Portal.
    Watch a video on how to optimize your support resource searches and check out more tips on the blogs.
  4. Chris
    Chris avatar
    20 posts
    Member since:
    Jan 2009

    Posted 29 Jan 2010 Link to this post

    Just thought I'd mention that I get this error about once a week on average. So far, it has been unreplicatable (which, apparently is a word I just made up).

    I feel for you all at Telerik. I myself have a handful of outstanding errors from code I have because I can't replicate them. Thanks for your help anyways!

    :-)

    Edit: One thing I *do* know is that it only happens with our site that is running under IIS 6. I never see this from our site that runs under IIS 7. Plus, the IIS 6 site only uses FileExplorer and AjaxPanel, but the IIS 7 site uses AjaxPanel, Calendar, ColorPicker, ComboBox, Dock, Grid, Input, ListBox, Menu, TabStrip, Upload, and Window.

    I don't expect anyone to solve the issue based on this info, but I just though I'd provide everything I knew... 
  5. Chris Behrens
    Chris Behrens avatar
    2 posts
    Member since:
    Oct 2009

    Posted 29 Jan 2010 Link to this post

    Look fellas...I don't want to be snarky, but how hard can this be? I can tell you the following, given the error dump:

    1. You have a call from code in " Telerik.Web.ScriptObjectBuilder" to " System.Web.UI.ScriptComponentDescriptor.AddEvent" that's having a problem.
    2. Specifically, the value passed to the "handler" argument, which is a string, is null or empty.
    3. The code, which resides in "Telerik.Web.ScriptObjectBuilder", is not generating a proper "handler" argument for that function call.
    4. It's intermittent and very difficult to replicate, so it's either reliant on some external resource which is changing, or it's a race condition (more likely).

    At the very least, you need to throw an exception when you can't generate a proper handler argument rather than passing the invalid value of null or empty to the next function.
  6. localman
    localman avatar
    29 posts
    Member since:
    Sep 2012

    Posted 02 Feb 2010 Link to this post

    +1 getting this error. has gone away for now. turned up out of nowhere.

    Some info about the system/config:

    Windows Server web 2008R2
    IIS 7
    Using .net MVC for routing in forms application.
  7. Iana Tsolova
    Admin
    Iana Tsolova avatar
    3388 posts

    Posted 04 Feb 2010 Link to this post

    Hello all,

    The best way to find the source of this error and provide a resolution to you is to give us a runnable sample of your scenario. We could then debug it and address all the issues accordingly.
    Other than this, there is no a lot more that could be done.

    Please excuse us we this caused you any inconvenience and thank you for your cooperation in advance.

    Best wishes,
    Iana
    the Telerik team

    Watch a video on how to optimize your support resource searches and check out more tips on the blogs.
    Follow the status of features or bugs in PITS and vote for them to affect their priority.
  8. Dana Hanna
    Dana Hanna avatar
    1 posts
    Member since:
    Nov 2009

    Posted 09 Feb 2010 Link to this post

    I absolutely agree with Chris.  Telerik is handling this completely unprofessionally.  This isn't rocket science, and it is clearly a bug that needs diagnosed.  We can't reproduce it with any consistency.

    if (handler == null) { 
      LogDiagnosticInformationToIdentifyTheEffingProblem(); 
      throw new SomeException()//or don't.  I'd suspect a fix would be to just ignore this and return...  but root cause is good to know. 
  9. Chris
    Chris avatar
    20 posts
    Member since:
    Jan 2009

    Posted 09 Feb 2010 Link to this post

    Um... I thought we *did* have access to the source code. But you are correct, it isn't "open source" in the sense that we can submit changes to be integrated into the main build.

    If I had the time, I could actually tweak the controls all I wanted. But, (1) I don't have the time, and (2) I would've branched without the ability to merge back to trunk.


  10. Matt Howeson
    Matt Howeson avatar
    8 posts
    Member since:
    May 2006

    Posted 09 Feb 2010 Link to this post

    Much as I have always found Telerik's support to be great for most issues I have raised, I tend to agree with Chris on this.

    We can't reproduce the prioblem, person after person has highlighted the same issue, and explained this is not replicable it happens sporadically.  We identified sometime ago that this seems to relate to a certain degree to the Application Pool recycling.

    It is not possible to replicate the error but it continues to occur regularly, we have a largeish asp.net application running with >200,000 lines of code, we can't send you the application it's just not feasible.  What we have done and various others have provided the stack trace identifying exactly where the error needs to be handled....

    We don't have access to handle this error, it happens outside our applications operation, the only people who can handle the error at this point when Telerik functions are being called is Telerik.  The standard response consistently to this thread is just no help to the people who have this issue, normally it's fair to say send us a sample project, but not in this instance it just doesn't always work like that.  You need to recognise that many of us see this error appearing regularly in our error logs, and our customers see an error screen they shouldn't, and it makes us your customers look bad.  Look at the stack trace, catch the error and handle it as best possible and then we can all move on.




  11. Yavor
    Admin
    Yavor avatar
    11 posts

    Posted 10 Feb 2010 Link to this post

    Hello,

    As mentioned previously, the options for pinpointing the problem, when it is not manifesting itself consistently, are limited. The most obvious one, of course, is a small working project. We do acknowledge, however, that this is not always possible. Nevertheless, if this is not available, the second best approach is to open a formal support ticket, and furnish as much details as possible:

    The development environment
    The frequency of the exception
    The stack trace of the page
    The relevant pages, which cause the exception
    More details on the control(s) used
    A live url to the site in question

    Additionally, although producing a small working project is not always straightforward, it is always possible - any unnecessary modules can be excluded, all unrelated controls can be removed temporarily. This does require some additional overhead, but is oftentimes the only way to go. Other than this, pinpointing the issue simply based on the stack trace is not a conceivable option.
    Further, since the scenarios supplied in this thread are rather different, opening a support ticket for the relevant control(s) would also allow us to further isolate the scenario, and provide more specific instructions.

    Sincerely yours,
    Yavor
    the Telerik team


    Watch a video on how to optimize your support resource searches and check out more tips on the blogs.
    Follow the status of features or bugs in PITS and vote for them to affect their priority.
Back to Top