This document summarizes news and features in C# and .NET 4.0, including named and default method parameters, interoperability with dynamic languages via the Dynamic Language Runtime (DLR), generics covariance and contravariance, exceptions handling improvements, application dump debugging, code contracts, application domain profiling, enhanced garbage collection, parallel computing features like Parallel LINQ and the Task Parallel Library, and references for further information. Key topics covered are using dynamic for interoperability while avoiding performance penalties, handling corrupted state exceptions, debugging .NET 4.0 application dumps in Visual Studio 2010, and demonstrations of threading constructs, PLINQ, TPL, and the unified cancellation model.

1. News in C# and NET 4.0 Iaşi, 20 februarie 2010 Florin Cardaşim, www.rms.ro

2. Agenda

3. C# 4 named and default params Named method parameters Default method parameter values

4. C# 4 & DLR Interop via Dynamic Language Runtime Dynamically-Typed Ruby Python Statically-Typed VB Dynamic Language Runtime C# Common Language Runtime

5. C# 4 & the DLR: dynamic Interop with dynamic languages like Ruby, Python Interop with COM

6. C# 4 – DLR Support: dynamic Interop always comes with a performance cost, so do not use dynamic if you don’t really need it

8. runtime performanceUse dynamic where appropriate

9. C# 4 & the DLR System.Numerics.BigInteger System.Numerics.Complex System.Tuples Tuple.Create(1,2,3,4,5,6,7,8) - maximum 8 members!! Property names are Item1, Item2, .., Item8 – ugly! Can be used as method params and return values Can be inherited Can be extended by extension methods Specifically useful in F# I’ll probably NOT use it in C#  http://msdn.microsoft.com/en-us/vcsharp/ee957397.aspx

10. Generics Covariance & Contravariance

11. Generics Co&Contravariance http://msdn.microsoft.com/en-us/library/dd799517(VS.100).aspx

12. Exceptions Management This code is bad! WHY?!!!

14. Exceptions Management For backwards compatibility use Or at application level

16. CLR 2.0: unhandled exception on secondary will ABORT the process

19. ABORT is better than a corrupted process

20. If your process ABORTs than there is a bug somewhere. GO FIX IT!

21. If you really need CSEs in your code use: [HandleProcessCorruptedStateExceptions] Or legacyCorruptedStateExceptionsPolicy enabled="true“

22. Net 4.0 application dump debugging When do we need a dump Crash, hang, performance analysis etc How to collect a dump adplus.vbs, DebugDiag etc Task Manager/Create Dump File VS2010/Debug/Save Dump As… How to analyze the dump Until now windbgonly for native apps Now VS2010 knows to debug .NET 4.0 app dump

23. Net 4.0 dump debugging Dump debugging with WinDbg

24. Net 4.0 dump debugging

26. Debug.Assert, Argument validation: if-then-throw

28. Required before a method can run

29. Postconditions

30. True at the completion of a method

31. Object invariants

36. Task Parallel Library (TPL)

39. Task Parallel Library (TPL)

42. Task Parallel Library (TPL)

45. Task Parallel Library (TPL)

48. www.rms.ro

49. www.codecamp.ro

50. www.Twitter.com/cardasim