Can someone explain what the C# “Func” does?

Question

I\'m reading the Pro MVC 2 book, and there is an example of creating an extension method for the HtmlHelper class.

Here the code example:

public stat         


        

Answer 1

A Func like

Func pageUrl = i => "Page" + i;

is a delegate accepting int as its sole parameter and returning a string. In this example, it accepts an int parameter with name i and returns the string "Page" + i which just concatenates a standard string representation of i to the string "Page".

In general, Func accepts one parameter that is of type TSource and returns a parameter of type TResult. For example,

Func toUpper = s => s.ToUpper();

then you can say

string upper = toUpper("hello, world!");

or

Func month = d => d.Month;

so you can say

int m = month(new DateTime(3, 15, 2011));