C#

<br />
    /// <summary><br />
    /// example of MultiThread<br />
    /// </summary><br />
    class MultiThread<br />
    {<br />
        Thread td_example = null;<br />
        System.Windows.Forms.Control _ctl;<br />
        public MultiThread(System.Windows.Forms.Control ctl)<br />
        {<br />
            td_example = new Thread(new ThreadStart(CalledMethod));<br />
            _ctl = ctl;<br />
        }<br />
<br />
        /// <summary><br />
        /// start the thread<br />
        /// </summary><br />
        public void startThread()<br />
        {<br />
            td_example.Start();<br />
        }<br />
<br />
        /// <summary><br />
        /// pause the thread<br />
        /// </summary><br />
        public void suspendThread()<br />
        {<br />
            td_example.Suspend();<br />
        }<br />
<br />
        /// <summary><br />
        /// stop the thread<br />
        /// Don't forget release the thread by this method<br />
        /// sometimes, the thread willn't exit and still run after the form closed<br />
        /// so, I suggest that to call this method before you want to close the main form.<br />
        /// </summary><br />
        public void abortThread()<br />
        {<br />
            td_example.Abort();<br />
        }<br />
<br />
        int i = 0;<br />
        private void CalledMethod()<br />
        {<br />
            //<br />
            // TODO:write your code here.<br />
            //<br />
            while (true)<br />
            {<br />
                i++;<br />
                System.Windows.Forms.MessageBox.Show(i.ToString());<br />
<br />
                Thread.Sleep(1000);<br />
            }<br />
        }<br />
    }<br />

using System;
using System.IO;
using System.Threading;
using System.Windows.Forms;

namespace MultiThreadedFileRead
{
    public partial class Form1 : Form
    {
        private readonly object _syncRoot = new object();

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                listBox1.Items.Add(openFileDialog1.FileName);
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            foreach (object file in listBox1.Items)
            {
                ThreadPool.QueueUserWorkItem(ThreadFunc, file);
            }
        }


        private void WouldBeEventHandler(string s)
        {
            if (InvokeRequired)
            {
                Action<string> d = WouldBeEventHandler;
                BeginInvoke(d, new object[]{s});
                return;
            }

            lock (_syncRoot)
            {
                listBox2.Items.Add(s);
            }
        }

        private void ThreadFunc(object state)
        {
            string filename = state as string;
            if (!string.IsNullOrEmpty(filename))
            {
                using (StreamReader fs = File.OpenText(filename))
                {
                    while (!fs.EndOfStream)
                    {
                        WouldBeEventHandler(fs.ReadLine());
                        Application.DoEvents();
                    }
                }
            }
        }
    }
}

using System;
using System.IO.Ports;
using System.Threading;
using System.Windows.Forms;

namespace MultiThreadedFileRead
{
    public partial class Form1 : Form
    {
        private readonly object _syncRoot = new object();

        public Form1()
        {
            InitializeComponent();
        }


        private void Form1_Load(object sender, EventArgs e)
        {
            serialPort1.DataReceived += SerialPort1DataReceived;
            serialPort2.DataReceived += SerialPort2DataReceived;
            serialPort3.DataReceived += SerialPort3DataReceived;
        }

        private void SerialPort1DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            ThreadPool.QueueUserWorkItem(ThreadFunc, sender);
        }

        private void SerialPort2DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            ThreadPool.QueueUserWorkItem(ThreadFunc, sender);
        }

        private void SerialPort3DataReceived(object sender, SerialDataReceivedEventArgs e)
        {
            ThreadPool.QueueUserWorkItem(ThreadFunc, sender);
        }

        private void ThreadFunc(object state)
        {
            SerialPort port = state as SerialPort;
            if (port != null)
            {
                try
                {
                    //do processing here.
                    
                }
                catch (Exception)
                {
                    //don't let the thread throw directly
                }
            }
        }
    }
}