.net 4.0 新特性

static void Main(string[] args)
        {
            Test(1);
            Test(par1: 1);
            Test(1, par2: 4);
            /* *
            Test(1, par2: 4, "");//前面使用了指定参数名赋值，后面必须也使用
             * */
        }

        private static void Test(int par1, int par2 = 2, string par3 = null)
        {

        }

Tuple<string, int, double> tuple = new Tuple<string, int, double>("", 1, 2d);
            Console.WriteLine("{0},{1},{2}", tuple.Item1, tuple.Item2, tuple.Item3);