C#实现获取本地内网(局域网)和外网(公网)IP地址的方法分析

/// <summary>
  /// 获取本机所有ip地址
  /// </summary>
  /// <param name="netType">"InterNetwork":ipv4地址，"InterNetworkV6":ipv6地址</param>
  /// <returns>ip地址集合</returns>
  public static List<string> GetLocalIpAddress(string netType)
  {
   string hostName = Dns.GetHostName();     //获取主机名称 
   IPAddress[] addresses = Dns.GetHostAddresses(hostName); //解析主机IP地址 

   List<string> IPList = new List<string>();
   if (netType==string.Empty)
   {
    for (int i = 0; i < addresses.Length; i++)
    {
     IPList.Add(addresses[i].ToString());
    }
   }
   else
   {
    //AddressFamily.InterNetwork表示此IP为IPv4,
    //AddressFamily.InterNetworkV6表示此地址为IPv6类型
    for (int i = 0; i < addresses.Length; i++)
    {
     if (addresses[i].AddressFamily.ToString() == netType)
     {
      IPList.Add(addresses[i].ToString());
     }
    }
   }
   return IPList;
  }

  List<string> ips= GetLocalIpAddress("");//获取本地所有ip
  List<string> ipv4_ips = GetLocalIpAddress("InterNetwork");//获取ipv4类型的ip
  List<string> ipv6_ips = GetLocalIpAddress("InterNetworkV6");//获取ipv6类型的ip

List<string> ipv4_ips = GetLocalIpAddress("InterNetwork");

List<string> ipv4_ips = GetLocalIpAddress("InterNetwork");

/// <summary>
  /// 获取页面html
  /// </summary>
  /// <param name="url">请求的地址</param>
  /// <param name="encoding">编码方式</param>
  /// <returns></returns>
  public static string HttpGetPageHtml(string url, string encoding)
  {
   string pageHtml = string.Empty;
   try
   {
    using (WebClient MyWebClient = new WebClient())
    {
     Encoding encode = Encoding.GetEncoding(encoding);
     MyWebClient.Headers.Add("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.84 Safari/537.36");
     MyWebClient.Credentials = CredentialCache.DefaultCredentials;//获取或设置用于向Internet资源的请求进行身份验证的网络凭据
     Byte[] pageData = MyWebClient.DownloadData(url); //从指定网站下载数据
     pageHtml = encode.GetString(pageData);
    }
   }
   catch (Exception e)
   {
    
   }
   return pageHtml;
  }
  /// <summary>
  /// 从html中通过正则找到ip信息(只支持ipv4地址)
  /// </summary>
  /// <param name="pageHtml"></param>
  /// <returns></returns>
  public static string GetIPFromHtml(String pageHtml)
  {
   //验证ipv4地址
   string reg = @"(?:(?:(25[0-5])|(2[0-4]\d)|((1\d{2})|([1-9]?\d)))\.){3}(?:(25[0-5])|(2[0-4]\d)|((1\d{2})|([1-9]?\d)))";
   string ip = "";
   Match m = Regex.Match(pageHtml, reg);
   if (m.Success)
   {
    ip = m.Value;
   }
   return ip;
  }

  var t0_html = HttpGetPageHtml("https://www.ip.cn", "utf-8");
  var t1_html = HttpGetPageHtml("http://www.ip138.com/ips138.asp", "gbk");
  var t2_html = HttpGetPageHtml("http://www.net.cn/static/customercare/yourip.asp", "gbk");
  var t0_ip = GetIPFromHtml(t0_html);// 111.198.29.123
  var t1_ip = GetIPFromHtml(t1_html);// 111.198.29.123
  var t2_ip = GetIPFromHtml(t2_html);// 111.198.29.123