public class _20210301_1
    {
        public void Run()
        {
            TestMethod("str1", 1, "para1", new int[] { 1, 2, 3 });

            TestMethod("str2");

            //TestMethod("str3",null); // 报错 Object reference not set to an instance of an object.”
        }

        public void TestMethod(string str,params object [] ps)
        {
            Console.WriteLine($"str:{str}");

            foreach(var p in ps)
            {
                Console.WriteLine(p);
            }
        }
    }