C# 套接字编程：Scoket，我用Scoket做的C# Windows应用程序如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;

namespace ServerForm.CommonCS
{
    public class PortHelper
    {

        /// <summary>
        /// 这个方法是验证某个端口是否可用
        /// </summary>
        /// <param name="port"></param>
        /// <returns></returns>
        public static bool IsAvaliable(int port)
        {

            Socket sk = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.IP);
            bool result = false;
            try
            {
                sk.Bind(new IPEndPoint(IPAddress.Any, port));//尝试绑定，因为如果该端口已经被使用，则无法绑定，会导致异常
                result = true;
            }
            catch
            {
                result = false;
            }
            finally
            {
                sk.Close();
            }

            return result;

        }

        /// <summary>
        /// 这个方法取得一个可用的端口
        /// </summary>
        /// <returns></returns>
        public static int GetAvaliablePort()
        {
            Random rnd = new Random();
            int port = rnd.Next(1024, 65535);//随机产生一个动态的端口号
            while (!IsAvaliable(port))
            {
                port = rnd.Next(1024, 65535);
            }

            return port;
        }

    }
}