New Cool Features of C# 4.0 [closed]

Answer 1

Tuples

Answer 2

the dynamic keyword looks like it can bridge the gap between dynamic languages like IronRuby or IronPython quite nicely, which will probably help its adoption in the Microsoft monoculture... that excites me.

While I'm intrigued by it, I'm also worried that it will be overused, like Generics and LINQ, SQLCLR, etc :)

Answer 3

Method parameter default values:

public void MyMethod1(string value1 = "test", int num1 = 10, double num2 = 12.2)
{
  //...
}

Also maybe anonymous return types:

public var MyMethod2()
{
  // ..
}

Answer 4

C#4.0

1) PLinq

2) Named and Optional Parameters

3) Lazy

4) Co & Contra Variance

5) Task Parallel

6) Dynamic object

7) Expando object

8) Improved COM-Interop

9)Tuple

only to name a few