using System; using System.Windows.Forms; public class TestLambdaExpression { public static void Main() { Action<string> messageTarget; if (Environment.GetCommandLineArgs().Length > 1) messageTarget = s => ShowWindowsMessage(s); else messageTarget = s => Console.WriteLine(s); messageTarget("Hello, World!"); } private static void ShowWindowsMessage(string message) { MessageBox.Show(message); } }