Yossi Dahan [BizTalk]


Sunday, July 20, 2008

Which System Exception?

I'm almost embarrassed to post this one, but it send me chasing windmills for a couple of hours, so if I can save that from any other unfortunate person it served a purpose I guess -

I have a call from one orchestration to another.

In the calling orchestration I wanted  to catch any exception that would occur on the called orchestration (or anywhere else down the line) and so I swiftly wrapped the call in a non-transactional scope and added an exception handler.

Being the keyboard-fan that I am (BizTalk is completely unfriendly to us keyboard types, but still...) when the type selector opened I did what I always do - I types the name of the class I wanted (System.Exception) and pressed enter.

The problem was that I did not type the class name ('Exception') but the full name ('System.Exception') and that got me System.SystemException class as the selected type, only that I did not realise that at the time.  apparently the type selector ignores special characters being keyed in?!

It was much later that I realised exceptions that were thrown in my called orchestration were not being caught in the calling one and even then it took me a good couple of hours to realise what was the reason (I simply did not look carefully enough at the exception type - System.SystemException just looks like System.Exception when you (well - I) glance at it!

Three take ways for me -

  1. Pay more attention when doing even the most trivial tasks. (trivial, isn't it?)
  2. Consider being less zealous about using the keyboard when doing BizTalk development
  3. But seriously - consider always having a general exception handler to catch whatever exceptions were not caught by other handlers. I should have been mostly covered by catching System.Exception (although BizTalk, unlike C# or VB.net does support exceptions that do not inherit from System.Exception, see Charles Young post on the subject), but this could have helped at least identify the problem.

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  • Hi Yossi,

    How did it escape the compiler? Surprised!! I haven't tested it myself, did the build succeeded without any errors?

    By Blogger Saravana Kumar, at 21/07/2008, 10:14  

  • Shouldn't bother the compiler - I simply ended up with an exception handler for the wrong Exception -
    I was handling System.SystemException (which was never thrown, and therefore never got caught...) when I intended to handle System.Exception which would have caught most Exceptions.

    By Blogger Yossi Dahan, at 21/07/2008, 15:48  

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