Windows下通过C#获取下指定进程监听的TCP/UDP端口号
作者：阿凡卢
出处： http://www.cnblogs.com/luxiaoxun/
1、在Windows下用CMD netstat命令可以获得当前进程监听端口号的信息，如netstat -ano可以看到IP、port、状态和监听的PID。

那么可以执行CMD这个进程得到监听的端口号信息，C#代码如下：

           //进程id
 
            int pid = ProcInfo.ProcessID;
 
             
 
            //存放进程使用的端口号链表
 
            List<int> ports = new List<int>();
 
 
 
            Process pro = new Process();
 
            pro.StartInfo.FileName = "cmd.exe";
 
            pro.StartInfo.UseShellExecute = false;
 
            pro.StartInfo.RedirectStandardInput = true;
 
            pro.StartInfo.RedirectStandardOutput = true;
 
            pro.StartInfo.RedirectStandardError = true;
 
            pro.StartInfo.CreateNoWindow = true;
 
            pro.Start();
 
            pro.StandardInput.WriteLine("netstat -ano");
 
            pro.StandardInput.WriteLine("exit");
 
            Regex reg = new Regex("\\s+", RegexOptions.Compiled);
 
            string line = null;
 
            ports.Clear();
 
            while ((line = pro.StandardOutput.ReadLine()) != null)
 
            {
 
                line = line.Trim();
 
                if (line.StartsWith("TCP", StringComparison.OrdinalIgnoreCase))
 
                {
 
                    line = reg.Replace(line, ",");
 
                    string[] arr = line.Split(',');
 
                    if (arr[4] == pid.ToString())
 
                    {
 
                        string soc = arr[1];
 
                        int pos = soc.LastIndexOf(':');
 
                        int pot = int.Parse(soc.Substring(pos + 1));
 
                        ports.Add(pot);
 
                    }
 
                }
 
                else if (line.StartsWith("UDP", StringComparison.OrdinalIgnoreCase))
 
                {
 
                    line = reg.Replace(line, ",");
 
                    string[] arr = line.Split(',');
 
                    if (arr[3] == pid.ToString())
 
                    {
 
                        string soc = arr[1];
 
                        int pos = soc.LastIndexOf(':');
 
                        int pot = int.Parse(soc.Substring(pos + 1));
 
                        ports.Add(pot);
 
                    }
 
                }
 
            }
 
            pro.Close();