>Hi everybody,
>
>The new question, if I may.
>
>1. How can I see the actual code of the system classes?
>
>2. Is the common practice to just trap the exceptions, say, if I want to add a user(s) to the role(s) and some of them are already in that role, I'm currently getting an exception with some helpful message.
>
>I'm reading about it as well in the meantime.
>
>Thanks in advance.
____

A partial anwer on (1)
http://en.wikipedia.org/wiki/.NET_Framework

On October 3, 2007, Microsoft announced that much of the source code for the .NET Framework Base Class Library (including ASP.NET, ADO.NET and Windows Presentation Foundation) will be made available with the final release of Visual Studio 2008 towards the end of 2007 under the shared source Microsoft Reference License.[1] The source code for other libraries including Windows Communication Foundation (WCF), Windows Workflow Foundation (WF) and Language Integrated Query (LINQ) will be added in future releases. Being released under the Microsoft Reference License means this source code is made available for debugging purpose only, primarily to support integrated debugging of the BCL in Visual Studio.

It should be in vs2008 - but I confess - have not found it