How to view CommandLineParser parsing errors in Visual Studio 2015?

Question

I'm trying to see the errors that occur when parsing command-line arguments using the CommandLineParser package and Visual Studio Professional 2015 (Update 3). Here is the code I'm working with:

using System;

using System.IO;



namespace SampleParser

{

    class Program

    {

        static void Main(string[] args)

        {

            // Set the CommandLineParser configuration options.

            var commandLineParser = new CommandLine.Parser(x =>

            {

                x.MutuallyExclusive = true;

                x.HelpWriter = Console.Error;

                x.IgnoreUnknownArguments = false;

            });



            // Parse the command-line arguments.

            var options = new CommandLineOptions();

            var optionsAreValid = commandLineParser.ParseArguments(args, options);



            if (!optionsAreValid)

            {

                return;

            }

        }

    }

}

I was expecting to see some helpful info about the problems that cause

optionsAreValid

to be set to false appear in the

Debug > Windows > Output

window. However, nothing's showing up... am I doing something wrong, am I looking in the wrong place, or are there other settings that need to be toggled before I'll see this info?

UPDATE #1

Here is the class that models the command line options after being (successfully) parsed:

namespace SampleParser

{

    class CommandLineOptions

    {

        [Option(HelpText = @"When set to ""true"", running the application will not make any changes.", Required = false)]

        public bool Preview { get; set; }





        [HelpOption]

        public string GetUsage()

        {

            return HelpText.AutoBuild(this, current => HelpText.DefaultParsingErrorsHandler(this, current));

        }

    }

}

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Answer 1

I mistakenly assumed that the HelpText property would send info to the Visual Studio Output window; however, I was wrong. Instead, it's how the CommandLineParser gets the info it needs to write info to the console window, which pops up when running a console application project (tx @NicoE ).

Here is some boilerplate code (targeting the v2.1.1-beta NuGet package) which, while still not giving me as much info as I'd like about parser errors, exposes them in a fashion that is easier for me to handle programmatically.

// Set the CommandLineParser configuration options.
var commandLineParser = new CommandLine.Parser(x =>
{
    x.HelpWriter = null;
    x.IgnoreUnknownArguments = false;
    //x.CaseSensitive = false;
});

// Parse the command-line arguments.
CommandLineOptions options;
var errors = new List<CommandLine.Error>();

var parserResults = commandLineParser.ParseArguments<CommandLineOptions>(args)
    .WithNotParsed(x => errors = x.ToList())
    .WithParsed(x => options = x)
;

if (errors.Any())
{
    errors.ForEach(x => Console.WriteLine(x.ToString()));
    Console.ReadLine();
    return;
}

How to view CommandLineParser parsing errors in Visual Studio 2015?

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