Using statement still causes Code analysis issues on 2 disposable objects

Question

 Using ms As New MemoryStream
    Dim st As New GZipStream(ms, CompressionMode.Compress, True)

    '... some code

    Return buffer
 End Using

And this:

dim As New MemoryStream
 using st As New GZipStream(ms, CompressionMode.Compress, True)

    '... some code

    Return buffer
 End Using

I had some legacy code which called Dispose() and Close() manually on the stream objects - this was causing CA2202 code analysis warnings about possible multiple calls to Dispose(). So I added using statements for both memory stream and gzipstream and the error didn't go away!?

If I used it on either the memorystream or gzipstream objects then the error then went away. Was is causing this behaviour?

Ivaylo Slavov · Accepted Answer · 2013-04-29T16:45:06.340

0

The reason may be, because the GZipStream is disposing of the underlying stream when its own Dispose method is called. Therefore, I'd recommend keeping the Using statement for the GZipStream only. At least, this is the behavior of most built-in stream wrappers in the .NET framework. For instance BufferedStream will close the underlying stream object when Close()/Dispose() is invoked (as per the MSDN documentation, behavior is explained in a comment in the code sample)

edited Apr 29 '13 at 16:45

answered Apr 29 '13 at 16:31

Ivaylo Slavov

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No, the error exists when using BOTH and goes away when only 1 using statement is used! – jaffa Apr 29 '13 at 16:32
@jaffa, see the edit, I revisited the answer. – Ivaylo Slavov Apr 29 '13 at 16:38
I thought this might be happening, thanks. – jaffa Apr 30 '13 at 07:47

Using statement still causes Code analysis issues on 2 disposable objects

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