在互联网上有几个地方告诉你如何获得一个IP地址。很多都像这个例子:

String strHostName = string.Empty;
// Getting Ip address of local machine...
// First get the host name of local machine.
strHostName = Dns.GetHostName();
Console.WriteLine("Local Machine's Host Name: " + strHostName);
// Then using host name, get the IP address list..
IPHostEntry ipEntry = Dns.GetHostEntry(strHostName);
IPAddress[] addr = ipEntry.AddressList;

for (int i = 0; i < addr.Length; i++)
{
    Console.WriteLine("IP Address {0}: {1} ", i, addr[i].ToString());
}
Console.ReadLine();

在这个例子中,我得到了几个IP地址,但我只对路由器分配给运行程序的计算机的IP地址感兴趣:例如,如果某人希望访问我计算机中的共享文件夹,我将给他的IP地址。

如果我没有连接到网络,我直接通过没有路由器的调制解调器连接到互联网,那么我希望得到一个错误。我如何才能看到我的计算机是否连接到网络与c#,如果它是然后得到局域网IP地址。


当前回答

我还在努力获取正确的IP。

我在这里尝试了各种解决方案,但没有一个能达到我想要的效果。几乎所有提供的条件测试都没有使用地址。

这是对我有效的方法,希望能有所帮助……

var firstAddress = (from address in NetworkInterface.GetAllNetworkInterfaces().Select(x => x.GetIPProperties()).SelectMany(x => x.UnicastAddresses).Select(x => x.Address)
                    where !IPAddress.IsLoopback(address) && address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork
                    select address).FirstOrDefault();

Console.WriteLine(firstAddress);

其他回答

我知道这可能是白费力气,但也许这能帮到别人。我到处寻找一种方法来找到我的本地IP地址,但我发现到处都说要使用:

Dns.GetHostEntry(Dns.GetHostName());

I don't like this at all because it just gets all the addresses assigned to your computer. If you have multiple network interfaces (which pretty much all computers do now-a-days) you have no idea which address goes with which network interface. After doing a bunch of research I created a function to use the NetworkInterface class and yank the information out of it. This way I can tell what type of interface it is (Ethernet, wireless, loopback, tunnel, etc.), whether it is active or not, and SOOO much more.

public string GetLocalIPv4(NetworkInterfaceType _type)
{
    string output = "";
    foreach (NetworkInterface item in NetworkInterface.GetAllNetworkInterfaces())
    {
        if (item.NetworkInterfaceType == _type && item.OperationalStatus == OperationalStatus.Up)
        {
            foreach (UnicastIPAddressInformation ip in item.GetIPProperties().UnicastAddresses)
            {
                if (ip.Address.AddressFamily == AddressFamily.InterNetwork)
                {
                    output = ip.Address.ToString();
                }
            }
        }
    }
    return output;
}

现在要获取以太网接口的IPv4地址:

GetLocalIPv4(NetworkInterfaceType.Ethernet);

或者你的无线接口:

GetLocalIPv4(NetworkInterfaceType.Wireless80211);

如果您试图获取无线接口的IPv4地址,但您的计算机没有安装无线卡,它将只返回一个空字符串。以太网接口也是如此。

编辑:

It was pointed out (thanks @NasBanov) that even though this function goes about extracting the IP address in a much better way than using Dns.GetHostEntry(Dns.GetHostName()) it doesn't do very well at supporting multiple interfaces of the same type or multiple IP addresses on a single interface. It will only return a single IP address when there may be multiple addresses assigned. To return ALL of these assigned addresses you could simply manipulate the original function to always return an array instead of a single string. For example:

public static string[] GetAllLocalIPv4(NetworkInterfaceType _type)
{
    List<string> ipAddrList = new List<string>();
    foreach (NetworkInterface item in NetworkInterface.GetAllNetworkInterfaces())
    {
        if (item.NetworkInterfaceType == _type && item.OperationalStatus == OperationalStatus.Up)
        {
            foreach (UnicastIPAddressInformation ip in item.GetIPProperties().UnicastAddresses)
            {
                if (ip.Address.AddressFamily == AddressFamily.InterNetwork)
                {
                    ipAddrList.Add(ip.Address.ToString());
                }
            }
        }
    }
    return ipAddrList.ToArray();
}

现在,这个函数将返回指定接口类型的所有分配地址。现在要获得单个字符串,可以使用. firstordefault()扩展名返回数组中的第一项,如果数组为空,则返回空字符串。

GetLocalIPv4(NetworkInterfaceType.Ethernet).FirstOrDefault();

获取本地Ip地址:

public static string GetLocalIPAddress()
{
    var host = Dns.GetHostEntry(Dns.GetHostName());
    foreach (var ip in host.AddressList)
    {
        if (ip.AddressFamily == AddressFamily.InterNetwork)
        {
            return ip.ToString();
        }
    }
    throw new Exception("No network adapters with an IPv4 address in the system!");
}

检查是否连接:

System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable ();

前提条件:你必须添加System.Data.Linq引用并引用它

using System.Linq;
string ipAddress ="";
IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
ipAddress = Convert.ToString(ipHostInfo.AddressList.FirstOrDefault(address => address.AddressFamily == AddressFamily.InterNetwork));

使用这些:

using System.Net;
using System.Net.Sockets;
using System.Net.NetworkInformation;
using System.Linq;

您可以使用一系列LINQ方法来获取最优先的IP地址。

public static bool IsIPv4(IPAddress ipa) => ipa.AddressFamily == AddressFamily.InterNetwork;

public static IPAddress GetMainIPv4() => NetworkInterface.GetAllNetworkInterfaces()
.Select((ni)=>ni.GetIPProperties())
.Where((ip)=> ip.GatewayAddresses.Where((ga) => IsIPv4(ga.Address)).Count() > 0)
.FirstOrDefault()?.UnicastAddresses?
.Where((ua) => IsIPv4(ua.Address))?.FirstOrDefault()?.Address;

这只是找到第一个具有IPv4默认网关的网络接口,并获得该接口上的第一个IPv4地址。 网络堆栈被设计为只有一个默认网关,因此具有默认网关的堆栈是最好的。

警告:如果你有一个不正常的设置,主适配器有多个IPv4地址,这将只抓取第一个。 (在这种情况下,抓取最佳的解决方案包括抓取网关IP,并检查哪个单播IP与网关IP地址在同一个子网中,这将杀死我们创建一个漂亮的基于LINQ方法的解决方案的能力,以及更多的代码)

过时了,这对我有用

public static IPAddress GetIPAddress()
{ 
 IPAddress ip = Dns.GetHostAddresses(Dns.GetHostName()).Where(address => 
 address.AddressFamily == AddressFamily.InterNetwork).First();
 return ip;
}