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MSMQ Async Bug?

Posted on 2004-07-31
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Last Modified: 2012-06-21
I have an application that is using MSMQ.

I have written an event handler to handle async message receiving.

it looks something like this :

Private Sub handler(ByVal objt00 As Object, ByVal objt01 As ReceiveCompletedEventArgs)
...
...
' SHOULD BE TRUE IF THERE IS A MESSAGE, FALSE IF TIMEOUT EXPIRED
If objt01.AsyncResult.IsCompleted Then
 ' process message
Else
 ' look to see if shutdown waithandle has occured
 ' if not, resume listening with BeginReceive(TimeSpan)
End If
...
...
End Sub

I initially call BeginReceive(TimeSpan) in a different function

The problem I have is that even if the timeout expires the AsyncResult.IsCompleted flag is true - and there are no messages to process
Has anyone else had this problem or know what I'm doing wrong?

Thanks.
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Question by:BJohnston
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Author Comment

by:BJohnston
ID: 11685576
As an addendum to my previous post, this is the MSDN documentation from which I am drawing my conclusions as to how the event handler should function. . .

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemmessagingmessagequeueclassbeginreceivetopic2.asp


note especially the portion that reads...

This overload specifies a time-out. If the interval specified by the timeout parameter expires, this component raises the ReceiveCompleted event, but the IsCompleted property of the operation's associated IAsyncResult is false. Because no message exists, a subsequent call to EndReceive will throw an exception.



I have temporarily patched this by simply catching the exception generated by the errant call to EndReceive and started BeginReceive again. . . sigh
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Expert Comment

by:gregoryyoung
ID: 11688722
intresting, the documentation agrees ... what if anything is the state of the result object at this point.
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Author Comment

by:BJohnston
ID: 11711154
Having talked with a Microsoft technical representative i have been informed that there is a documentation error and that regardless of what triggers the callback (either a Message arrival or a timeout) the AsyncResult.IsCompleted flag will be true.
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Expert Comment

by:gregoryyoung
ID: 11711163
documentation error ... hmm ... sounds more like a functionality flaw to me :)
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Author Comment

by:BJohnston
ID: 11913425
Please refund points as there was no answer to be had.  Thank you.
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modulo earned 0 total points
ID: 11946782
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