Sys.ArgumentTypeException: Object of type 'Sys._Application' cannot be converted to type 'Sys._Application

3 posts, 0 answers
  1. Jacques
    Jacques avatar
    138 posts
    Member since:
    Jun 2007

    Posted 29 Jan 2012 Link to this post

    We've been experiencing a JavaScript problem with the RadControls for the past few days: 
    Error: "Sys.ArgumentTypeException: Object of type 'Sys._Application' cannot be converted to type 'Sys._Application'.
    Parameter Name: instance

    Symptoms: The problem intermittently switches between IE6 and most other browsers. For example, if we rebuild the solution and hit the page with IE6 we don't see the exception, but if we then go to Firefox we'll see those exceptions in Firebug. If we then rebuild again and hit the page with Firefox first, it will be fine, but then IE6 starts reporting these errors. In non-IE6 browsers the error won't occur then. 

    System information: version = 4.0
    Telerik version = 2011.3.1115.40
    IIS 7.5 

    Solutions we had tried
    1. Disabled smart navigation in the web.config file
    2. Set the script mode of the script manager to release
    3. Set debug = false in the web.config
    None of which solved the problem...

    We did discover in the end that in the RadWindow that was being shown had a button on it with its RegisterWithScriptManager set to false. When this is set to true the problem disappeared. 

    Question That Still Remain
    When we were initially trying to isolate the problem we had commented out the JavaScript code that launched the modal window, meaning the window wasn't being shown at all and yet the exception was still raised. The javascript code we did use was window.setUrl and, so we commented out the line that called the show method. Why would this error then still come up? Is it possible that the setUrl method instantiates the window in the background without calling show()? 

    Hope this saves someone else the countless days it took us to figure out where the problem was coming from. 


  2. Marin Bratanov
    Marin Bratanov avatar
    5929 posts

    Posted 30 Jan 2012 Link to this post

    Hello Jacques,

    I am glad to hear you have resolved the situation and thank you for sharing your experience with the community.

    Now, to your question - yes, you are correct that setUrl() creates the UI of the RadWindow and thus loads the content thaw was causing your issue. This is the way the control works and it needs to be so - in a scenario where setUrl() is called and the RadWindow's UI is not yet created and we do not create it explicitly a JavaScript error would be thrown, which should not be allowed to happen. Moreover, we must set the URL as this would be the expected behavior - although it is not shown it has the desired URL so it can be shown properly at a later stage. I hope this clears the reason for this behavior and why it cannot be changed.

    All the best,
    the Telerik team
    If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed now
  3. Jacques
    Jacques avatar
    138 posts
    Member since:
    Jun 2007

    Posted 30 Jan 2012 Link to this post

    Hi Marin,

    Thanks for the explanation. We're certainly not wanting anything changed. Just the explanation was needed, it helps us understand what to expect from the behavior.

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