New CSharp Language features 3.0 and 4.0

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The content for this page is being written and not complete yet. Its content should not be relied on at the moment.

New features

C# 3.0

• see http://www.codeproject.com/KB/cs/csharp3.aspx
• see http://soumya.wordpress.com/2009/06/12/new-features-in-c-part-ii-c-3-0/

Implicitly Typed Local Variables (aka 'Local Variable Type Inference')

• At first glance this feature looks like it does what the 'dreaded' VARIANT Type of Visual Basic 6 does, where it results in late-bound Type Inference which can cause very difficult-to-spot errors at runtime.
• However, Implicitly Typed Local Variables result in early-bound strongly-typed code, which is way better as its VB 6 'colleague' as it can not cause those errors at run-time!
• Only works for local variables in a method (that is, not for Class Fields or Method Arguments).
• Usage
  • Use new var keyword for the declaration of such variables.
  • Should not be over-used as the source code is less explicit then when the Type it holds is stated explicitly.
  • Can be a time saver for declaration of long Types, esp. Generic Types; there it fine to be used and actually can result in easier-to-read code.
• Usage example in OpenPetra source code: none yet.
• Details: [1]

Auto-implemented Properties (aka 'Automatic Properties')

• used already in the web server for conference backend. saves writing dumb code

Object Initializers

• used by ext.net which is used by the web server for conference backend.

Partial Methods

• Available in Partial Classes only.

Lambda Expressions

• Replace Anonymous Methods, which were new in C# 2.0.

C# 4.0

• see http://www.codeproject.com/KB/cs/CSharp4Features.aspx
• see http://soumya.wordpress.com/2009/06/12/new-features-in-c-part-iii-c-4-0/

Named Parameters

• This looks most interesting for us.

Optional Parameters

• This looks very interesting for us, too.

COM Interop

• Probably not interesting for us as the OpenPetra Client should stay platform-independent (COM is available only on Windows OS's).
• Could potentially be useful for optional plug-ins for the OpenPetra Client that would need COM to fulfill their roles, though. Obviously those plug-ins would work on only Windows OS's then.

Mono and new C# features

TODO