c# - 如何在 C# 中更改 DNS IP 地址

Question

为了在我的 WPF 应用程序中以编程方式更改我的适配器 (NetworkInterface) DNS IP 地址，我遵循了这个问题：Change DNS in windows using c# answer 并添加如下：

    /// <summary>
    /// Method to set the DNS IP addresses of a given <see cref="NetworkInterface"/>
    /// Note : using "Win32_NetworkAdapterConfiguration" library, so only on Windows OS
    /// </summary>
    /// <param name="ni">The <see cref="NetworkInterface"/> adapter to modify its DNS IP addresses along given <paramref name="addresses"/></param>
    /// <param name="addresses">The IP addresses to store in <paramref name="ni"/> adapter as its new DNS IP addresses</param>
    public static void SetDNS(this NetworkInterface ni, string[] addresses)
    {
        if (ni == null) return;

        ManagementClass objMC = new ManagementClass("Win32_NetworkAdapterConfiguration");
        ManagementObjectCollection objMOC = objMC.GetInstances();
        foreach (ManagementObject objMO in objMOC)
        {
            if ((bool)objMO["IPEnabled"])
            {
                if (objMO["Caption"].ToString().Contains(ni.Description))
                {
                    ManagementBaseObject objdns = objMO.GetMethodParameters("SetDNSServerSearchOrder");
                    if (objdns != null)
                    {
                        objdns["DNSServerSearchOrder"] = addresses;
                        objMO.InvokeMethod("SetDNSServerSearchOrder", objdns, null);
                    }
                }
            }
        }
    }

进入调试模式表明它正确调用了这个函数，循环通过ManagementObjectCollection，结束其中一项正确匹配我的2if语句，最后调用

objdns["DNSServerSearchOrder"] = addresses;
                            objMO.InvokeMethod("SetDNSServerSearchOrder", objdns, null);

见：https ://imgur.com/a/TowMWnT

但是当我使用ipconfig /allCLI 检查时，我的 DNS IP 地址没有更改！如何通过 C# 直接在 Windows 中有效地更改我的 DNS 地址，而不是通过调用后面的 cmd.exe 进程。

谢谢你。

标签： c#dns

Answer 1

所以这就是我改变我的系统 DNS 地址的结果。感谢@jimi 帮助我更好地理解这一点。

因此，正如@jimi 所指出的那样，毕竟我正在默默地使用netsh 来设置新的DNS 地址，因为我尝试的原始解决方案不支持IPv6（通过WMI）

到目前为止（没有彻底测试它）它工作！

这是我所做的：

    /// <summary>
    /// Start a <see cref="Process"/>
    /// </summary>
    /// <param name="processName">The <see cref="ProcessStartInfo.FileName"/> (usually name of the exe / command to start)</param>
    /// <param name="args">The <see cref="ProcessStartInfo.Arguments"/> (the argument of the command)</param>
    /// <param name="verb">The <see cref="ProcessStartInfo.Verb"/>. Use "runas" to start the process with admin priviledge (default is null)</param>
    /// <param name="useShell">The <see cref="ProcessStartInfo.UseShellExecute"/>. Does the process run silently or not (silent by default)</param>
    /// <param name="redirectErros">The <see cref="ProcessStartInfo.RedirectStandardError"/>. Do we redirect standard error ? (true by default)</param>
    /// <param name="redirectOutput">The <see cref="ProcessStartInfo.RedirectStandardOutput"/>. Do we redirect standard output ? (true by default)</param>
    /// <param name="noWindow">The <see cref="ProcessStartInfo.CreateNoWindow"/>. Do we prevent the creation of CMD window to run silently ? (silent by default)</param>
    /// <returns>True if <paramref name="processName"/> isn't null and process execution succeeded. False if <paramref name="processName"/> is null or empty.
    /// Throw an <see cref="Exception"/> if execution failed</returns>
    public static bool StartProcess(string processName, string args, string verb = null, bool useShell = false, bool redirectErros = true, bool redirectOutput = true, bool noWindow = true)
    {
        if (string.IsNullOrWhiteSpace(processName))
            return false;
        ProcessStartInfo psi = new ProcessStartInfo();
        psi.FileName = processName;
        psi.Arguments = args;
        psi.UseShellExecute = useShell;
        psi.RedirectStandardOutput = redirectOutput;
        psi.RedirectStandardError = redirectErros;
        psi.CreateNoWindow = noWindow;
        if (verb != null)
            psi.Verb = verb;
        Process proc = Process.Start(psi);
        proc.WaitForExit();
        string errors = proc.StandardError.ReadToEnd();
        string output = proc.StandardOutput.ReadToEnd();
        if (proc.ExitCode != 0)
            throw new Exception(processName + " exit code: " + proc.ExitCode.ToString() + " " + (!string.IsNullOrEmpty(errors) ? " " + errors : "") + " " + (!string.IsNullOrEmpty(output) ? " " + output : ""));
        return true;
    }

    /// <summary>
    /// Convinient method to start a "netsh" process as admin to set a new DNS IP address calling <see cref="StartProcess(string, string, string, bool, bool, bool)"/>
    /// </summary>
    /// <param name="interfaceName">The name of the interface to set its new <paramref name="address"/> IP ddress</param>
    /// <param name="address">The new IP address to set of the <paramref name="interfaceName"/> DNS</param>
    /// <param name="isPrimary">Is this new DNS IP address is a primary one ?</param>
    /// <returns><see cref="StartProcess(string, string, string, bool, bool, bool)"/> return value, 
    /// or false if <paramref name="address"/> isn't a correct IP address</returns>
    public static bool netshSetNewDNS(string interfaceName, string address, bool isPrimary)
    {
        var ipVer = IPversion(address, RGXVX);
        if (!(ipVer[0] || ipVer[1]))
            return false;
        return netshSetNewDNS(interfaceName, address, isPrimary, ipVer[0]);
    }

    /// <summary>
    /// Convinient method to start a "netsh" process as admin to set a new DNS IP address calling <see cref="netshSetNewDNS(string, string, bool)"/>
    /// </summary>
    /// <param name="interfaceName">The name of the interface to set its new <paramref name="address"/> IP ddress</param>
    /// <param name="address">The new IP address to set of the <paramref name="interfaceName"/> DNS</param>
    /// <param name="isPrimary">Is this new DNS IP address is a primary one ?</param>
    /// <param name="isIPv6">Does <paramref name="address"/> is IPv6 ?</param>
    /// <returns><see cref="netshSetNewDNS(string, string, bool)"/> return value</returns>
    public static bool netshSetNewDNS(string interfaceName, string address, bool isPrimary, bool isIPv6)
    {            
        string arg = string.Format("interface {0} {1} dnsservers \"{2}\"{3} {4} {5}", isIPv6 ? "ipv6" : "ipv4", isPrimary ? "set" : "add", interfaceName, isPrimary ? " static" : "", address, isPrimary ? "primary" : "index=2");
        return StartProcess("netsh", arg, "runas");
    }

    /// <summary>
    /// Method to set the DNS IP addresses of a given <see cref="NetworkInterface"/>
    /// note : we use netsh silently.
    /// see : https://www.tenforums.com/tutorials/77444-change-ipv4-ipv6-dns-server-address-windows.html
    /// </summary>
    /// <param name="ni">The <see cref="NetworkInterface"/> adapter to modify its DNS IP addresses along given <paramref name="addresses"/></param>
    /// <param name="ipv4">The IPv4 addresses to store in <paramref name="ni"/> adapter as its new DNS IP addresses</param>
    /// <param name="ipv6">The IPv6 addresses to store in <paramref name="ni"/> adapter as its new DNS IP addresses</param>
    public static void SetDNS(this NetworkInterface ni, string[] ipv4, string[] ipv6)
    {
        if (!(ipv4.Any(add => IsIP(add, RGXV4)) || ipv6.Any(add => IsIP(add, RGXV6))))
        {
            Debug.WriteLine("None of the suplied addresses are IPv4/6.\nCan not update DNS IP addresses.");
            return;
        }
        // delete current IPv4 DNS
        StartProcess("netsh", "interface ipv4 delete dnsservers \"" + ni.Name + "\" all", "runas");
        // delete current IPv6 DNS
        StartProcess("netsh", "interface ipv6 delete dnsservers \"" + ni.Name + "\" all", "runas");
        string address;
        //set new IPv4 DNS addresses
        if (ipv4 != null && ipv4.Length>0)
        {                
            //primary
            address = ipv4[0];                
            try
            { bool res = netshSetNewDNS(ni.Name, address, true, false); }
            catch(Exception e)
            { Debug.WriteLine(e.Message); }
            if (ipv4.Length>1)
            {
                //secondary
                address = ipv4[1];
                try
                { bool res = netshSetNewDNS(ni.Name, address, false, false); }
                catch (Exception e)
                { Debug.WriteLine(e.Message); }
            }
        }
        
        //set new IPv6 DNS addresses
        if (ipv6 != null && ipv6.Length > 0)
        {
            
            //primary
            address = ipv6[0];
            try
            { bool res = netshSetNewDNS(ni.Name, address, true, true); }
            catch (Exception e)
            { Debug.WriteLine(e.Message); }

            if (ipv6.Length > 1)
            {
                //secondary
                address = ipv6[1];
                try
                { bool res = netshSetNewDNS(ni.Name, address, false, true); }
                catch (Exception e)
                { Debug.WriteLine(e.Message); }
            }
        }
    }

我虽然有 1 个“次要”问题：设置 ipv6 (+ipv4 ?) 解决了性能问题。

而只有新的 (2) 个 ipv4 IP 地址几乎是立即的（最多 1 秒），使用 2 个 ipv6 + 2 个 ipv4 设置，在实际（正确）更改我的 DNS IP 地址之前最多需要 10 秒。

调试显示它冻结了在辅助 IPv4 DNS 地址设置上调用proc.WaitForExit();的函数（在 中）！StartProcess(...)SetDNS(...) bool res = netshSetNewDNS(ni.Name, address, false, false);

奇怪的是，它总是在这里冻结，因为当我只使用 2 个新的 IPv4 DNS 地址设置进行呼叫时，这次它不会冻结......