Func and Action

In this chapter you will learn:

  1. How to use Func and Action from system namespace

Func and Action from System namespace

C# System namespace defines several generic delegates to convert almost all possible method signatures.

delegate TResult Func <out TResult>  ();
delegate TResult Func <in T, out TResult>  (T arg);
delegate TResult Func <in T1, in T2, out TResult>  (T1 arg1, T2 arg2);
/*from   j a  va 2s.c  o  m*/
... and so on, up to T16

delegate void Action  ();
delegate void Action <in T>  (T arg);
delegate void Action <in T1, in T2>  (T1 arg1, T2 arg2);

... and so on, up to T16

We can rewrite the printer delegate as follows.

using System;//from  j  av  a2 s .  c o m
class Test
{
    static void output(int[] intArray, Action<int> p)
    {
        foreach (int i in intArray)
        {
            p(i);
        }
    }
    static void consolePrinterInt(int i)
    {
        Console.WriteLine(i);
    }
    static void Main()
    {
        Action<int> p = consolePrinterInt;
        int[] intArray = new int[] { 1, 2, 3 };
        output(intArray, p);
    }
}

The output:

Next chapter...

What you will learn in the next chapter:

  1. Using new operator with delegate
Home » C# Tutorial » delegate, lambda, event
delegate
Multicast delegate
delegate variables
delegate parameters
Generic delegate
delegate return
Func and Action
delegate new
chained delegate
Anonymous delegate
delegate array
Return a delegate
delegate as parameter
Event
event multicast
static event
EventHandler
Event pattern
lambda
lambda syntax
Func, Action and lambda
lambda with outer function
lambda iteration variables