using System;

using System.CommandLine;   

using System.CommandLine.Invocation;    

​

​

public class Program

{

    public static void Main()

    {

        var subCmd = new Command("sub-cmd") { new Argument<string>("sub-cmd-arg") };

        subCmd.Handler = CommandHandler.Create<string, string>(SubCmdHadnler);

​

        var cmd = new Command("cmd") { new Argument<string>("cmd-arg"), subCmd };

        cmd.Handler = CommandHandler.Create<string>(CmdHadnler);

​

        new RootCommand() { cmd }.Invoke("cmd 11 sub-cmd 22");

    }

​

    static void SubCmdHadnler(string cmdArg, string subCmdArg)

    {

        Console.WriteLine($"subCmd = {subCmdArg}");

        CmdHadnler(cmdArg);

    }

​

    static void CmdHadnler(string cmdArg)

    {

        // Why is there no output ！！！！！！！！！！！

        Console.WriteLine($"cmd = {cmdArg}");

    }

}