Why should I upgrade to c# 4.0?

Question

I know there are some nice new features in C# 4.0 but I can't, for the life of me, think of a compelling reason for either upgrading existing projects or for switching to new projects.

I've seen some posts where people have said that if their hosting service didn't provide .Net 4 that they'd find another provider as .Net 4 was pinicle to their direction <?>.

Now my boss is trying to get me to agree to switch all our production environments to C# 4 and to do it now.

So the question is has anyone either began using, or converted a project to, C# 4 for a compelling reason? Was there a feature that you just had to have that would make your life so much easier?

Answer 1

There are some cool new features in C# 4.0:

• Dynamic member lookup
• Covariant and contravariant generic type parameters
• Optional ref Keyword when using COM
• Optional parameters and named arguments
• Indexed properties

In his release blog post Scott Guthrie goes into detail about the features of .NET 4 in general. Another great resource is a white paper at http://www.asp.net/learn/whitepapers/aspnet4. However, I'd doubt you are going to need one / any of these new features right away. As Scott Hanselman blogged:

there's a lot of stuff that's new and added in .NET 4, but not in that "overwhelming-I-need-to-relearn-everything" way.

Whether or not you should upgrade is therefore dependent on a variety of other factors. Some reasons that spring to mind:

• Standardizing your development environment on a single platform VS2010 over VS2008.
• Size of the .NET Framework is substantially reduced
• Speed improvements if you are a Visual Studio Tools for Office developer

An open dialogue with your manager seems appropriate to understand his reasoning for the upgrade. I'd argue that because it's shiny isn't a compelling reason.

As a reference this dated Stack Overflow question "Why not upgrade to the latest .net framework" provides the inverse to your question.

Answer 2

• Quite frankly System.Collections.Concurrent has made developing multi-threaded applications a breeze.

• The new and improved System.Linq.Expressions makes writing dynamically compiled code seem like child's play.

• The new named parameters feature means I can have big constructors and not get confused as to what each parameter is. Immutable objects are just that much easier.

Answer 3

Surprisingly not mentioned:

• PLINQ
• Task Parallel Library