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Categories / C# Book / 01 Language Basics
 

0194 Func, Action and lambda

lambda expression are often used with Func and Action delegates. Func and Action are predefined delegates with generic parameters. 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); ... 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 Here is an example of how use to use Func to create a lambda expression. using System; class Program { public static void Main() { Func<int, int> sqr = x => x * x; Console.WriteLine(sqr(3)); } } The output: 9