You might want to check out some of the interception examples that are out on the web... There's actually quite a lot of them... Furthermore, Don Box does a great job describing the CLR's facilities for method-call interception in his book on the Runtime [1]. Then there are also two MSDN-Magazine articles on this topic [2, 3].
HTH,
Stefan
[1] Don Box. Essential .NET, Volume I: The Common Language Runtime. Addison Wesley. 2000. [2] Dharma Shukla, Simon Fell, and Chris Sells. 'Aspect-Oriented Programming Enables Better Code Encapsulation and Reuse', in: MSDN Magazine. 17 (3). Microsoft. March 2002. http://msdn.microsoft.com/msdnmag/issues/02/03/AOP/default.aspx [3] Juval Lowy. 'Decouple Components by Injecting Custom Services into Your Object's Interception Chain', in: MSDN Magazine. 18 (3). Microsoft. March 2003. http://msdn.microsoft.com/msdnmag/issues/03/03/ContextsinNET/default.aspx
(beware of line breaks!)
From: "Howard Dierking" <[EMAIL PROTECTED]> To: "Moderated discussion of advanced .NET topics." <[EMAIL PROTECTED]> Subject: Need to Append a line to an existing method Date: Thu, 29 May 2003 17:12:00 -0400
I'm working on creating a transparent auditing system whereby methods can be flagged for auditing using attributes and the system, implemented in the object or the object base class can process audit information.
The approach that I've taken thusfar is to create a custom attribute (basically data only), and create a base class that goes through the type information to determine which methods are flagged for auditing.
My thought at this point is to, when a method is found that requires auditing, append a line of code to that method (calling a _WriteAudit_ method) and immediately recompile. In the Reflection.Emit namespace, I can see how I could build methods from scratch -- however, I don't see how to edit a method.
Also, concerned about the performance implications of this approach -- especially if there is a more standard approach for accomplishing my aforementioned goal. thoughts?
_howard
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