What is an anonymous function in C#?

An anonymous function is an “inline” statement or expression that can be used wherever a delegate type is expected. You can use it to initialize a named delegate or pass it instead of a named delegate type as a method parameter.

There are two kinds of anonymous functions:

• Lambda Expressions
• Anonymous Methods

Consider:

// Original delegate syntax required 
// initialization with a named method.
TestDelegate testDelA = new TestDelegate(M);

// C# 2.0: A delegate can be initialized with
// inline code, called an "anonymous method." This
// method takes a string as an input parameter.
TestDelegate testDelB = delegate(string s) {
 Console.WriteLine(s);
};

// C# 3.0. A delegate can be initialized with
// a lambda expression. The lambda also takes a string
// as an input parameter (x). The type of x is inferred by the compiler.
TestDelegate testDelC = (x) => {
 Console.WriteLine(x);
};

// Invoke the delegates.
testDelA("Hello. My name is M and I write lines.");
testDelB("That's nothing. I'm anonymous and ");
testDelC("I'm a famous author.");