ネイティブIPの取得マルチNICの場合を考慮

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Text.RegularExpressions;

namespace _09 IP_ _
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine(GetLocalIP());

            Console.ReadKey();
        }

        /// <summary>
        ///  IP
        /// </summary>
        /// <returns></returns>
        public static string GetLocalIP()
        {
            string result = RunApp("route", "print", true);
            Match m = Regex.Match(result, @"0.0.0.0\s+0.0.0.0\s+(\d+.\d+.\d+.\d+)\s+(\d+.\d+.\d+.\d+)");
            if (m.Success)
            {
                return m.Groups[2].Value;
            }
            else
            {
                try
                {
                    System.Net.Sockets.TcpClient c = new System.Net.Sockets.TcpClient();
                    c.Connect("www.baidu.com", 80);
                    string ip = ((System.Net.IPEndPoint)c.Client.LocalEndPoint).Address.ToString();
                    c.Close();
                    return ip;
                }
                catch (Exception)
                {
                    return null;
                }
            }
        }


        /// <summary>
        ///  。
        /// </summary>
        /// <param name="filename"> </param>
        /// <param name="arguments"> </param>
        /// <returns></returns>
        public static string RunApp(string filename, string arguments, bool recordLog)
        {
            try
            {
                if (recordLog)
                {
                    Trace.WriteLine(filename + " " + arguments);
                }
                Process proc = new Process();
                proc.StartInfo.FileName = filename;
                proc.StartInfo.CreateNoWindow = true;
                proc.StartInfo.Arguments = arguments;
                proc.StartInfo.RedirectStandardOutput = true;
                proc.StartInfo.UseShellExecute = false;
                proc.Start();

                using (System.IO.StreamReader sr = new System.IO.StreamReader(proc.StandardOutput.BaseStream, Encoding.Default))
                {
                    string txt = sr.ReadToEnd();
                    sr.Close();
                    if (recordLog)
                    {
                        Trace.WriteLine(txt);
                    }
                    if (!proc.HasExited)
                    {
                        proc.Kill();
                    }
                    return txt;
                }
            }
            catch (Exception ex)
            {
                Trace.WriteLine(ex);
                return ex.Message;
            }
        }
    }
}