Check port

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net.Sockets;

namespace KiemTraPort
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        /// <summary>
        /// Kiem tra port nao mo tu 1 den 1024
        /// </summary>
        private void btCheck_Click(object sender, EventArgs e)
        {
            tbPort.Text = "Please wait...";
            TcpClient client = new TcpClient();
            int iPort;
            String strListPost = "";
            for (iPort = 1; iPort <= 1024; iPort++)
            {
                client = new TcpClient();
                try
                {
                    client.Connect(tbIP.Text, iPort);
                    strListPost += iPort.ToString() + " ";
                    //tbPort.Text = strListPost;
                }
                catch (Exception ex)
                {
                    //MessageBox.Show(ex.Message);
                }
            }
            tbPort.Text = strListPost;
            MessageBox.Show("Check finish!");
        }
    }
}