Meaning of () => Operator in C#, if it exists

Question

I read this interesting line here, in an answer by Jon Skeet.

The interesting line is this, where he advocated using a delegate:

Log.Info("I did something: {0}", () => action.GenerateDescription()); 

Question is, what is this ()=> operator, I wonder? I tried Googling it but since it's made of symbols Google couldn't be of much help, really. Did I embarrassingly miss something here?

Answer 1

This introduces a lambda function (anonymous delegate) with no parameters, it's equivalent to and basically short-hand for:

delegate void () { return action.GenerateDescription(); } 

You can also add parameters, so:

(a, b) => a + b 

This is roughly equivalent to:

delegate int (int a, int b) { return a + b; } 

Answer 2

=> this is lambda operator. When we don't have any input parameters we just use round brackets () before lambda operator.

syntax: (input parameters) => expression