C#获取局域网ip段

      static void Main()
        {          
            ArrayList list = GetAllLocalMachines();
            for (int i = 0; i < list.Count; i++)
            {
                Console.WriteLine(list[i]);
            }          
            Console.ReadKey();
        }

 //首先来个循环ping一下那个网段的主机。
        //其次用以下的函数去获取所有的局域网内有响应的ip地址列表
        public static ArrayList GetAllLocalMachines()
        {
            Process p = new Process();
            p.StartInfo.FileName = "cmd.exe";
            p.StartInfo.UseShellExecute = false;
            p.StartInfo.RedirectStandardInput = true;
            p.StartInfo.RedirectStandardOutput = true;
            p.StartInfo.RedirectStandardError = true;
            p.StartInfo.CreateNoWindow = true;
            p.Start(); p.StandardInput.WriteLine("arp -a");
            p.StandardInput.WriteLine("exit");
            ArrayList list = new ArrayList();
            StreamReader reader = p.StandardOutput;//读取ip。mac。。。。
            string IPHead = Dns.GetHostByName(Dns.GetHostName()).AddressList[0].ToString().Substring(0, 3);
            for (string line = reader.ReadLine(); line != null; line = reader.ReadLine())
            {
                line = line.Trim(); if (line.StartsWith(IPHead) && (line.IndexOf("动态") != -1))
                {
                    string IP = line.Substring(0, 15).Trim(); string Mac = line.Substring(line.IndexOf("-") - 2, 0x11).Trim();

                    list.Add(IP);
                }
            }
            return list;
        }