I mentioned type inference in a previous post, but I don't think I mentioned lambda expressions, which is a new feature of C# 3.0. The lambda operator, btw, is "=>".

Lambda expressions provide a cleaner way to do anonymous methods. In fact, lamba expressions area actually converted to delegates and compile to the same IL code.

so this...

delegate( int val ) { return val * val; };

is essentially equivalent to this...
x => x * x;

With type inference, the type of a local variable is inferred from the expression used to define it. Use the "var" keyword.

For example...

int i = 42;
 string[] ss = new string[] { "Hello", "world" };
 Dictionary<Person, List<Student>> people = (some expression);

are equivalent to...

var i = 42;
 var ss = new string[] { "Hello", "world" };
 var people = (some expression);

You can also create an anonymous type on the fly... something like this:

Person p = bll.People.Get(42);
 var anonType = new { First = p.FirstName, Last = p.LastName };</p> <p>Console.WriteLine ( "{0} {1}", anonType.First, anonType.Last );