①

 private void GetIP()
 {
     string hostName = Dns.GetHostName();//本机名
     //System.Net.IPAddress[] addressList = Dns.GetHostByName(hostName).AddressList;//会警告GetHostByName()已过期，我运行时且只返回了一个IPv4的地址
     System.Net.IPAddress[] addressList = Dns.GetHostAddresses(hostName);//会返回所有地址，包括IPv4和IPv6
     foreach (IPAddress ip in addressList)
     {
         listBox1.Items.Add(ip.ToString());
     }
} 

②使用IPHostEntry获取本机局域网地址

static string GetLocalIp()
{
 string hostname = Dns.GetHostName();//得到本机名
 //IPHostEntry localhost = Dns.GetHostByName(hostname);//方法已过期，只得到IPv4的地址
 IPHostEntry localhost = Dns.GetHostEntry(hostname);
 IPAddress localaddr = localhost.AddressList[0];
 return localaddr.ToString();
}

 方法时通过向网站向一些提供IP查询的网站发送webrequest，然后分析返回的数据流

string strUrl = "提供IP查询的网站的链接";
Uri uri = new Uri(strUrl);
WebRequest webreq = WebRequest.Create(uri);
Stream s = webreq .GetResponse().GetResponseStream();
StreamReader sr = new StreamReader(s, Encoding.Default);
string all = sr.ReadToEnd();
int i = all.IndexOf("[") + 1;
//分析字符串得到IP
return ip;
/*
我用的是http://www.ip.cn/getip.php?action=getip&ip_url=&from=web
(这种链接很容易找的，百度“IP”得到一些网站，分析一下网站的链接就能得到)
返回的数据是：
<div class="well"><p>当前 IP：<code>0.0.0.0</code>&nbsp;来自：XX省XX市 电信</p><p>GeoIP: Beijing, China</p></div>
解析这段就行
*/

⑥通过获取CMD里ipconfig命令的结果来得到IP

private void GetIP6()
{
  Process cmd = new Process();
  cmd.StartInfo.FileName = "ipconfig.exe";//设置程序名
  cmd.StartInfo.Arguments = "/all";  //参数
  //重定向标准输出
  cmd.StartInfo.RedirectStandardOutput = true;
  cmd.StartInfo.RedirectStandardInput = true;
  cmd.StartInfo.UseShellExecute = false;
  cmd.StartInfo.CreateNoWindow = true;//不显示窗口（控制台程序是黑屏）
  //cmd.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;//暂时不明白什么意思
  /*
  收集一下 有备无患
  关于:ProcessWindowStyle.Hidden隐藏后如何再显示？
  hwndWin32Host = Win32Native.FindWindow(null, win32Exinfo.windowsName);
  Win32Native.ShowWindow(hwndWin32Host, 1);     //先FindWindow找到窗口后再ShowWindow
  */
  cmd.Start();
  string info = cmd.StandardOutput.ReadToEnd();
  cmd.WaitForExit();
  cmd.Close();
  textBox1.AppendText(info);
}

⑦NetworkInformation

private void GetIP5()
{
  //需要的命名空间
  //using System.Net.NetworkInformation;
  //using System.Net.Sockets;
  string str = "";
  NetworkInterface[] adapters = NetworkInterface.GetAllNetworkInterfaces();
  int i = 0;
  foreach (NetworkInterface adapter in adapters)
  {
    IPInterfaceProperties adapterProperties = adapter.GetIPProperties();
    UnicastIPAddressInformationCollection allAddress = adapterProperties.UnicastAddresses;
    if (allAddress.Count > 0)
    {
        str += "interface   " + i + "description: \t " + adapter.Description + " ";
        i++;
        foreach (UnicastIPAddressInformation addr in allAddress)
        {
            if (addr.Address.AddressFamily == AddressFamily.InterNetworkV6)
            {
                ipListComb.Items.Add(addr.Address);
            }
            if (addr.Address.AddressFamily == AddressFamily.InterNetwork)
            {
                comboBox1.Items.Add(addr.Address);
            }
        }
    }
  }
  MessageBox.Show(str);
}