Form1.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Net;
using System.Net.Sockets;
using System.IO;
using System.Threading;
using System.Text.RegularExpressions;
using System.Runtime.InteropServices;
using System.Media;
using System.Diagnostics;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        #region variables
        public static string userName = "blahblah";
        public static string password = "oauth:blahblah";
        private static IrcClient irc = new IrcClient("irc.chat.twitch.tv", 6667, userName, password);
        NetworkStream serverStream = default(NetworkStream);
        string readData = "";
        Thread chatThread;
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            irc.joinRoom("larklen");
            chatThread = new Thread(getMessage);
            chatThread.Start();
        }

        private void getMessage()
        {
            serverStream = irc.tcpClient.GetStream();
            int buffsize = 0;
            byte[] inStream = new byte[10025];
            buffsize = irc.tcpClient.ReceiveBufferSize;
            while (true)
            {
                try
                {
                    readData = irc.readMessage();
                    msg();
                }
                catch (Exception)
                {

                }
            }
        }

        private void msg()
        {
            if (this.InvokeRequired) this.Invoke(new MethodInvoker(msg));
            else
            {
                string[] separator = new string[] { "#larklen :" };
                string[] singlesep = new string[] { ":", "!" };

                if (readData.Contains("PRIVMSG"))
                {
                    string username = readData.Split(singlesep, StringSplitOptions.None)[1];
                    string message = readData.Split(separator, StringSplitOptions.None)[1];


                    richTextBox1.Text = richTextBox1.Text + username + "> " + message + Environment.NewLine;

                    int num = richTextBox1.Lines.Count();
                    if (richTextBox1.Lines.Count() > 301)
                    {
                        var foos = new List<string>(richTextBox1.Lines);
                        foos.RemoveAt(0);
                        richTextBox1.Lines = foos.ToArray();
                    }
                }
            }
        }

    }
}
#endregion