C# 獲取本機可用端口

System.Net.NetworkInformation命名空間下提供IPGlobalProperties類，用來提供本地計算機有關的網絡連接信息，獲取本機可用端口的使用方式如下：

using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.Net.NetworkInformation;
using System.Linq;

namespace Common
{
    public class AvailablePort
    {
        private const int MaxPort= 65535;

        /// <summary>
        /// 獲取所有可用的TCP端口
        /// </summary>
        /// <param name="startPort"></param>
        /// <returns></returns>
        public static List<int> GetAllAvailableTCPPort(int startPort = 1000)
        {
            //提供本地計算機有關網絡連接信息
            IPGlobalProperties iPGlobalProperties = IPGlobalProperties.GetIPGlobalProperties();
            //獲取可用的TCP監聽終結點信息
            IPEndPoint[] iPEndPoints = iPGlobalProperties.GetActiveTcpListeners();
            return iPEndPoints.Where(q => q.Port >= startPort && q.Port <= MaxPort).Select(q => q.Port).ToList();
        }

        /// <summary>
        /// 獲取所有可用的UDP端口
        /// </summary>
        /// <param name="startPort"></param>
        /// <returns></returns>
        public static List<int> GetAllAvailableUDPPort(int startPort = 1000)        {
            //提供本地計算機有關網絡連接信息
            IPGlobalProperties iPGlobalProperties = IPGlobalProperties.GetIPGlobalProperties();
            //獲取可用的UDP監聽終結點信息
            IPEndPoint[] iPEndPoints = iPGlobalProperties.GetActiveUdpListeners();
            return iPEndPoints.Where(q => q.Port >= startPort && q.Port <= MaxPort).Select(q => q.Port).ToList();
        }

        /// <summary>
        /// 獲取所有TCP連接
        /// </summary>
        /// <param name="startPort"></param>
        /// <returns></returns>
        public static void GetAllTCPConnect(int startPort = 1000)
        {
            //提供本地計算機有關網絡連接信息
            IPGlobalProperties iPGlobalProperties = IPGlobalProperties.GetIPGlobalProperties();
            //獲取TCP連接信息
            TcpConnectionInformation[] iPEndPoints = iPGlobalProperties.GetActiveTcpConnections();
            foreach (var item in iPEndPoints)
            {
                Console.WriteLine($"Local:{item.LocalEndPoint.Address},Remote:{item.RemoteEndPoint.Address},State:{item.State}");
            }
        }
    }
}