可以'；t在C#中将域解析为IP

本文关键字：IP 可以 | 更新日期: 2023-09-27 18:00:36

我有这个代码：

IPEndPoint serverEndPoint = new IPEndPoint(IPAddress.Parse(txtBoxIP.Text), MainForm.port);

例如，当我在txtBoxIP（192.168.1.2）中有一个IP时，它工作得很好。

但是如果我想放一个DNS？就像我把（my.selfip.com）我得到：

System.FormatException: An invalid IP address was specified.
at System.Net.IPAddress.InternalParse(String ipString, Boolean tryParse)

如何使它同时支持IP和DNS？

可以'；t在C#中将域解析为IP

IPAddress ipAddress;
if (!IPAddress.TryParse (txtBoxIP.Text, out ipAddress))
   ipAddress = Dns.GetHostEntry (txtBoxIP.Text).AddressList[0];
serverEndPoint = new IPEndPoint(ipAddress, MainForm.port)

不要忘记错误处理。

DNS名称不是IP地址。有关DNS解析，请参阅Dns.GetHostEntry()。

编辑后添加：以下是我所做的：

public static IPEndPoint CreateEndpoint( string hostNameOrAddress , int port )
{
  IPAddress addr    ;
  bool      gotAddr = IPAddress.TryParse( hostNameOrAddress , out addr ) ;
  if ( !gotAddr )
  {
    IPHostEntry dnsInfo = Dns.GetHostEntry( hostNameOrAddress ) ;
    addr = dnsInfo.AddressList.First() ;
  }
  IPEndPoint instance = new IPEndPoint( addr , port ) ;
  return instance ;
}

DNS到IP列表

IPHostEntry nameToIpAddress;
nameToIpAddress = Dns.GetHostEntry("HostName");
foreach (IPAddress address in nameToIpAddress.AddressList)
    Console.WriteLine(address.ToString());

然后您可以使用地址列表中的IP。

这是一篇很棒的文章

var input = txtBoxIP.Text;
IPAddress ip;
// TryParse returns true when IP is parsed successfully
if (!IPAddress.TryParse (input, out ip))
    // in case user input is not an IP, assume it's a hostname
    ip = Dns.GetHostEntry (input).AddressList [0]; // you may use the first one
// note that you'll also want to handle input errors
// such as invalid strings that are neither IPs nor valid domains,
// as well as hosts that couldn't be resolved
var serverEndPoint = new IPEndPoint (ip, MainForm.port);

注意：不，这不是似曾相识，这个答案与我在另一个重复问题上提供的答案完全相同。。。我想让这篇文章的作者意识到另一个，所以我找到的最好的方法是在这里再次添加它，因为在Stack Overflow上，仅仅链接到其他答案是不受欢迎的

我有一个非常巧妙的扩展方法！

我考虑到IPV6可能会作为DNS类返回的地址列表中的第一个地址返回，并允许您根据结果"青睐"IPV6或IPV4。这是一个完全文档化的类（为了简洁起见，只使用了本例的相关方法）：

using System;
using System.Linq;
using System.Net;
using System.Net.Sockets;
/// <summary>
/// Basic helper methods around networking objects (IPAddress, IpEndPoint, Socket, etc.)
/// </summary>
public static class NetworkingExtensions
{
    /// <summary>
    /// Converts a string representing a host name or address to its <see cref="IPAddress"/> representation, 
    /// optionally opting to return a IpV6 address (defaults to IpV4)
    /// </summary>
    /// <param name="hostNameOrAddress">Host name or address to convert into an <see cref="IPAddress"/></param>
    /// <param name="favorIpV6">When <code>true</code> will return an IpV6 address whenever available, otherwise 
    /// returns an IpV4 address instead.</param>
    /// <returns>The <see cref="IPAddress"/> represented by <paramref name="hostNameOrAddress"/> in either IpV4 or
    /// IpV6 (when available) format depending on <paramref name="favorIpV6"/></returns>
    public static IPAddress ToIPAddress(this string hostNameOrAddress, bool favorIpV6=false)
    {
        var favoredFamily = favorIpV6 ? AddressFamily.InterNetworkV6 : AddressFamily.InterNetwork;
        var addrs = Dns.GetHostAddresses(hostNameOrAddress);
        return addrs.FirstOrDefault(addr => addr.AddressFamily == favoredFamily)
               ??
               addrs.FirstOrDefault();
    }
}

别忘了把这个类放在命名空间中！：-）

现在你可以简单地这样做：

var server = "http://simpax.com.br".ToIPAddress();
var blog = "http://simpax.codax.com.br".ToIPAddress();
var google = "google.com.br".ToIPAddress();
var ipv6Google = "google.com.br".ToIPAddress(true); // if available will be an IPV6

您必须自己查找主机名的IP：

string addrText = "www.example.com";
IPAddress[] addresslist = Dns.GetHostAddresses(addrText);
foreach (IPAddress theaddress in addresslist)
{
   Console.WriteLine(theaddress.ToString());
}

编辑

为了区分两者（顺便说一句，这使用了C#的一些功能，可能在3.5及以上）：

bool isDomain = false;
foreach(char c in addrText.ToCharArray())
{
   if (char.IsLetter(c)){
     isDomain = true;
     break;
}
if (isDomain)
   // lookup IP here
else
   // parse IP here
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