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

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;
}

其他回答

用Linq更新Mrchief的答案,我们会有:

public static IPAddress GetLocalIPAddress()
{
   var host = Dns.GetHostEntry(Dns.GetHostName());
   var ipAddress= host.AddressList.FirstOrDefault(ip => ip.AddressFamily == AddressFamily.InterNetwork);
   return ipAddress;
}

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)

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 ();

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;
}

这是我发现的最好的代码,以获得当前的IP,避免获得VMWare主机或其他无效的IP地址。

public string GetLocalIpAddress()
{
    UnicastIPAddressInformation mostSuitableIp = null;

    var networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();

    foreach (var network in networkInterfaces)
    {
        if (network.OperationalStatus != OperationalStatus.Up)
            continue;

        var properties = network.GetIPProperties();

        if (properties.GatewayAddresses.Count == 0)
            continue;

        foreach (var address in properties.UnicastAddresses)
        {
            if (address.Address.AddressFamily != AddressFamily.InterNetwork)
                continue;

            if (IPAddress.IsLoopback(address.Address))
                continue;

            if (!address.IsDnsEligible)
            {
                if (mostSuitableIp == null)
                    mostSuitableIp = address;
                continue;
            }

            // The best IP is the IP got from DHCP server
            if (address.PrefixOrigin != PrefixOrigin.Dhcp)
            {
                if (mostSuitableIp == null || !mostSuitableIp.IsDnsEligible)
                    mostSuitableIp = address;
                continue;
            }

            return address.Address.ToString();
        }
    }

    return mostSuitableIp != null 
        ? mostSuitableIp.Address.ToString()
        : "";
}