(精华)2020年6月26日 C#类库 Ip地址帮助类

using System.Collections;
using System.Net;
using System.Net.NetworkInformation;
using System.Net.Sockets;

namespace Core.Util
{
    /// <summary>
    /// Ip地址帮助类
    /// </summary>
    public class IpHelper
    {
        #region 外部接口

        /// <summary>
        /// 获取本地IP地址
        /// </summary>
        /// <returns></returns>
        public static string GetLocalIp()
        {
            UnicastIPAddressInformation mostSuitableIp = null;
            var networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();

            foreach (var network in networkInterfaces)
            {
                if (network.OperationalStatus != OperationalStatus.Up)
                    continue;
                var properties = network.GetIPProperties();
                if (properties.GatewayAddresses.Count == 0)
                    continue;

                foreach (var address in properties.UnicastAddresses)
                {
                    if (address.Address.AddressFamily != AddressFamily.InterNetwork)
                        continue;
                    if (IPAddress.IsLoopback(address.Address))
                        continue;
                    return address.Address.ToString();
                }
            }

            return mostSuitableIp != null
                ? mostSuitableIp.Address.ToString()
                : "";
        }

        /// <summary>
        /// 获取第一个可用的端口号
        /// </summary>
        /// <returns></returns>
        public static int GetFirstAvailablePort()
        {
            int BEGIN_PORT = 1024;//从这个端口开始检测
            int MAX_PORT = 65535; //系统tcp/udp端口数最大是65535            

            for (int i = BEGIN_PORT; i < MAX_PORT; i++)
            {
                if (PortIsAvailable(i)) return i;
            }

            return -1;
        }

        /// <summary>
        /// 检查指定端口是否已用
        /// </summary>
        /// <param name="port"></param>
        /// <returns></returns>
        public static bool PortIsAvailable(int port)
        {
            bool isAvailable = true;

            IList portUsed = PortIsUsed();

            foreach (int p in portUsed)
            {
                if (p == port)
                {
                    isAvailable = false; break;
                }
            }

            return isAvailable;
        }

        #endregion

        #region 私有成员

        /// <summary>
        /// 获取操作系统已用的端口号
        /// </summary>
        /// <returns></returns>
        private static IList PortIsUsed()
        {
            //获取本地计算机的网络连接和通信统计数据的信息
            IPGlobalProperties ipGlobalProperties = IPGlobalProperties.GetIPGlobalProperties();

            //返回本地计算机上的所有Tcp监听程序
            IPEndPoint[] ipsTCP = ipGlobalProperties.GetActiveTcpListeners();

            //返回本地计算机上的所有UDP监听程序
            IPEndPoint[] ipsUDP = ipGlobalProperties.GetActiveUdpListeners();

            //返回本地计算机上的Internet协议版本4(IPV4 传输控制协议(TCP)连接的信息。
            TcpConnectionInformation[] tcpConnInfoArray = ipGlobalProperties.GetActiveTcpConnections();

            IList allPorts = new ArrayList();
            foreach (IPEndPoint ep in ipsTCP) allPorts.Add(ep.Port);
            foreach (IPEndPoint ep in ipsUDP) allPorts.Add(ep.Port);
            foreach (TcpConnectionInformation conn in tcpConnInfoArray) allPorts.Add(conn.LocalEndPoint.Port);

            return allPorts;
        }

        #endregion
    }
}