开始尝试

using System;

namespace MyConsoleApp
{
    class Program
    {
        static void Main(string region = null,
            string session = null,
            string package = null,
            string project = null,string[] args=null)
        {
            Console.WriteLine("来到了主方法");
            #region Main
            switch (region)
            {
                case "say_hello":
                    SayH();
                    break;
                case "what_the_cat_says":
                    Console.WriteLine(new Cat().Say());
                    break;
                case "run3":
                    Cat.Run3();
                    break;
            }
            #endregion
        }

        static void SayH(){
            #region say_hello
            Console.WriteLine($"Hello World 王欢欢!{new Cat().Say()}");
            #endregion

        }
    }
}

using System;

namespace MyConsoleApp
{
    class Program
    {
        static void Main(string region = null,
            string session = null,
            string package = null,
            string project = null,string[] args=null)
        {
            Console.WriteLine("来到了主方法");
            #region Main
            switch (region)
            {
                case "say_hello":
                    SayH();
                    break;
                case "what_the_cat_says":
                    Console.WriteLine(new Cat().Say());
                    break;
                case "run3":
                    Cat.Run3();
                    break;
            }
            #endregion
        }

        static void SayH(){
            #region say_hello
            Console.WriteLine($"Hello World 王欢欢!{new Cat().Say()}");
            #endregion

        }
    }
}

结束啦 :cry