public static void Foo(params string[] lines)
       { 
           foreach (string l in lines) {  
                Console.Write(l);  
             } 
        }

        public static void Main() 
       {  
             string[] data = new string[] { "1", "2", "3" };     
             Foo(data); 
             Foo("A", "B", "C"); 
        }