ChatLibrary for S&box

Command.cs

using System;
using System.Collections.Generic;

namespace ChatLibrary
{
    public static class Command
    {

        public delegate void Callback(List<string> arguments);
        private static Dictionary<string, Callback> Commands = new Dictionary<string, Callback>();

        public static bool Add(string command, Callback onCommand)
        {
            try
            {
                Commands.Add(command, onCommand);
                return true;
            }
            catch (ArgumentException)
            {
                return false;
            }
        }

        public static void Remove(string command)
        {
            Commands.Remove(command);
        }

        public static Parser.Data Call(string chatText)
        {

            Parser chatParser = new Parser(chatText);
            Parser.Data CommandData = chatParser.GetCommandData();

            if (CommandData.validParse)
            {
                Callback ChatCommand;
                if (Commands.TryGetValue(CommandData.command, out ChatCommand))
                {
                    ChatCommand(CommandData.arguments);
                }
            }

            return CommandData;

        }
    }

}

Parser.cs

using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;

namespace ChatLibrary
{
    public class Parser
    {

        public const string pattern = "('.*?'|\".*?\"|\\S+)";

        public struct Data
        {
            public bool validParse;
            public char prefix;
            public string command;

            public int argumentsCount;
            public List<string> arguments;
        }

        public Data CommandData;

        public Parser(string chatText)
        {

            CommandData.validParse = false;
            CommandData.argumentsCount = 0;
            CommandData.arguments = new List<string>();

            if (chatText.Length > 1)
            {
                Parse(chatText);
                ValidateParse();
            }
        }

        public void Parse(string chatText)
        {
            
            CommandData.prefix = chatText[0];

            Regex rgx = new Regex(pattern, RegexOptions.IgnoreCase);
            MatchCollection matches = rgx.Matches(chatText.Substring(1));

            if (matches.Count > 0)
            {
                CommandData.command = matches[0].Value;
                CommandData.argumentsCount = matches.Count - 1;

                for ( int index = 1; index < matches.Count; index++)
                {
                    CommandData.arguments.Add(matches[index].Value);
                }
            }
            
        }

        public void ValidateParse()
        {
            if (!Char.IsPunctuation(CommandData.prefix)) return;
            if (CommandData.argumentsCount != CommandData.arguments.Count) return;
            CommandData.validParse = true;
        }

        public Data GetCommandData()
        {
            return CommandData;
        }
    }
}

Program.cs

using System;
using System.Collections.Generic;

namespace ChatLibrary
{

    public static class Program
    {

        public static void Main()
        {

            Console.WriteLine("Running test program");

            Command.Add("hello", (List<string> Args) => {
                int argc = 1;
                foreach (string argument in Args)
                {
                    Console.Write("Argument {0}: {1}\n", argc++, argument);
                }
            });

            Command.Call("!hello world \"and all you awesome\" guys");
            Console.ReadKey();
        }

    }

}