mscorlib 2.0.0.0 4.0.0.0 Contravariant System.Delegate `` System.Void The type. The object on which to perform an action. A delegate to a method that returns no values, and takes one parameter. Since the compiler can infer the types, you do not need to provide the type, this is typically used with the method or the 's ForEach method. `// // Simple "echo" implementation // using System; class X { static void Main (string [] args) { Array.ForEach (args, print); Console.WriteLine (); } static void print (string a) { Console.Write (a); Console.Write (" "); } }`