如何通过hostname获取已使用IPv6协议的IPv4地址

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Web;

namespace FXBVT_Team.CheckFilePath
{
    public class IPNetworking
    {
        public static string GetIP4Address(string hostAddress)
        {
            string IP4Address = String.Empty;

            foreach (IPAddress IPA in Dns.GetHostAddresses(hostAddress))
            {
                if (IPA.AddressFamily.ToString() == "InterNetwork")
                {
                    IP4Address = IPA.ToString();
                    break;
                }
            }

            if (IP4Address != String.Empty)
            {
                return IP4Address;
            }

            foreach (IPAddress IPA in Dns.GetHostAddresses(Dns.GetHostName()))
            {
                if (IPA.AddressFamily.ToString() == "InterNetwork")
                {
                    IP4Address = IPA.ToString();
                    break;
                }
            }

            return IP4Address;
        }

    }
}