Is there a situation in which Dispose won't be called for a 'using' block?

This was a telephone interview question I had: Is there a time when Dispose will not be called on an object whose scope is declared by a using block?

My answer was no - even if an exception happens during the using block, Dispose will still be called.

The interviewer disagreed and said if using is wrapped in a try-catch block then Dispose will not be called by the time you enter the catch block.

This goes contrary to my understanding of the construct, and I haven't been able to find anything that backs up the interviewers point of view. Is he correct or might I have misunderstood the question?

c# dispose using

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The interviewer is partially right. Dispose may not correctly clean up the underlying object on a case-by-case basis.

WCF for example has a few known issues if an exception is thrown while in a using block. Your interviewer was probably thinking of this.

Here is an article from MSDN on how to avoid issues with the using block with WCF. Here is Microsoft's official workaround, although I now think that a combination of that answer and this one is the most elegant approach.

answered 2011-11-19T04:48:38.200

Is there a situation in which Dispose won't be called for a 'using' block?

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