// @nuget: CommandLineParser -Version 2.6.0

//https://github.com/commandlineparser/commandline/issues/523

using System;

using CommandLine;

​

    public class Program

    {

          public static void Main()

        {

            UseCase("-vv", "-vv");  

            UseCase("-vvv", "-vvv");    

            UseCase("-vvvv", "-vvvv");

             //using int values 

            UseCase("-v1", "-v1");  

            UseCase("-v2", "-v2");  

            UseCase("-v3", "-v3");  

            UseCase("no argument, so use default value 1", ""); 

            //UseCase("-v", "-v");  //Not allowed, raise error: Option 'v' has no value.

        }

        public static void UseCase(string title, string argsCommand)

        {

            Console.WriteLine("*****Args: "+title + " ******");

            var parser = new Parser(with => 

                {                   

                    with.HelpWriter = Console.Out;

                });

            var args=argsCommand.Split();

            //args.Dump();

            var result = parser.ParseArguments<Options>(args);

            result.WithParsed(options => 

            {

                Console.WriteLine("Current Arguments: -v {0}\n" ,options.Verbosity);                

            })

            .WithNotParsed(errs => errs.Dump());

        }      

    }

​

  enum VerbosityEnum

        {

            v = 1,

            vv = 2,

            vvv = 3,

        }

   class Options

       {

           [Option(

               'v',

               HelpText = "Verbosity level: v or vv or vvv Or int values 1 or 2 or 3",

               Default=VerbosityEnum.v)]

           public VerbosityEnum Verbosity { get; set; }

       }