C#如何获取本机的外网ip地址？

C#如何获取本机的外网ip地址？

源码如下：

 public static string GetextenalIP()
           {
            //获取外部IP  
            String url = "http://hijoyusers.joymeng.com:8100/test/getNameByOtherIp";
            string IP = "未获取到外网ip";
            try
            {
                //从网址中获取本机ip数据  
                System.Net.WebClient client = new System.Net.WebClient();
                client.Encoding = System.Text.Encoding.Default;
                string str = client.DownloadString(url);
                client.Dispose();

                if (!str.Equals("")) IP = str;
                else IP = GetExtenalIpAddress_0();
            }
            catch (Exception) { }

            return IP;

        }
        public static string GetExtenalIpAddress_0()
        {
            string IP = "未获取到外网ip";
            try
            {
                //从网址中获取本机ip数据  
                System.Net.WebClient client = new System.Net.WebClient();
                client.Encoding = System.Text.Encoding.Default;
                string str = client.DownloadString("http://1111.ip138.com/ic.asp");
                client.Dispose();

                //提取外网ip数据 [218.104.71.178]  
                int i1 = str.IndexOf("["), i2 = str.IndexOf("]");
                IP = str.Substring(i1 + 1, i2 - 1 - i1);
            }
            catch (Exception) { }

            return IP;

        }

如何调用获取ip地址？

可以将ip地址写入label标签中

label.text= GetextenalIP();