News In The Net40

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

Agenda

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

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

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

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

C# 4 – DLR Support: dynamic
Don’t abuse dynamic in C# because you loose:
compile time type checking and intellisense
runtime performance
Use dynamic where appropriate

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

Generics Covariance & Contravariance

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

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

What is the problem?
(Exception ex) might be a Corrupted State Exception (CSE) , like Access Violation, Invalid Memory, Divide By Zero, Stack Overflow
What to do if Exception is CSE?
Your process and data are in danger. ABORT.
Are other actions possible?
What is CLR 4.0 doing?
CLR 4.0 will NOT deliver CSEs to our code by default
catch(Exception ex) will NOT catch the CSE
Your process will ABORT

For backwards compatibility use
Or at application level

A bit of history:
CLR1.1: unhandled exceptions (on secondary threads) will NOT abort process
CLR 2.0: unhandled exception on secondary will ABORT the process
CLR 4.0: CSEs not handled by catch(Exception), process will ABORT
Conclusions:
Do not handle exceptions if you don’t know how
ABORT is better than a corrupted process

Conclusions:
Only catch exceptions that you can handle
ABORT is better than a corrupted process
If your process ABORTs than there is a bug somewhere. GO FIX IT!
If you really need CSEs in your code use:
[HandleProcessCorruptedStateExceptions]
Or
legacyCorruptedStateExceptionsPolicy enabled="true“

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

Net 4.0 dump debugging
Dump debugging with WinDbg

Net 4.0 dump debugging

Code Contracts
Until CLR 4.0
Code comments
Debug.Assert, Argument validation: if-then-throw
Unit tests?
In CLR 4.0 we have System.Diagnostics.Contracts
Preconditions
Required before a method can run
Postconditions
True at the completion of a method
Object invariants
Conditions that are always true

App Domain Profiling
A host application may profile the activity of the hosted applications (for example add-ins) and attempt to restart it if takes too many resources
DEMO: “MonitoringIsEnabled”

Enhanced GC
Concurrent GC
Can NOT do Gen0, Gen1 GC (ephemeral segment) at the same time with Gen2 GC

Enhanced GC
Backgound GC
CAN do a Gen0, Gen1 GC (ephemeral segment) while doing Gen2 GC

Enhanced GC
Concurrent GC
Background GC
Latency during application execution

Parallel Computing in .NET 4
Why should we care about parallel computing?
Because we care about application performance
Because our CPUs/cores are not used at full capacity
System.Threading
Barrier
CountdownEvent
Parallel Extensions
Parallel LINQ (PLINQ)
Task Parallel Library (TPL)
Coordination Data Structures – System.Colllectiions.Concurrent
Unified cancellation model
CancellationTokenSource, CancellationToken

Demo: System.Threading, UCM
System.Threading
Barrier
CountdownEvent
Parallel Extensions
Coordination Data Structures (CDS)

Demo: Parallel LINQ
System.Threading
Barrier
CountdownEvent
Parallel Extensions

Demo: Task Parallel Library
System.Threading
Barrier
CountdownEvent
Parallel Extensions

References
MSDN
MSDN Magazine
Channel9
VS2010 Training Kit
Msdn.blogs.com/Tess

Please fill the evaluation form !!!
Thank you very much
Florin Cardasim
florin.cardasim@rms.ro
www.rms.ro
www.codecamp.ro
www.Twitter.com/cardasim

News In The Net40

by Florin Cardasim on Feb 24, 2010

Accessibility

Categories

Tags

Upload Details

Usage Rights

1 Embed 5

Statistics

News In The Net40 — Presentation Transcript