Programmatically Set Browser Proxy Settings in C#

Question

I'm writing an winforms app that needs to set internet explorer's proxy settings and then open a new browser window. At the moment, I'm applying the proxy settings by going into the registry:

RegistryKey registry = Registry.CurrentUser.OpenSubKey("Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings", true);
registry.SetValue("ProxyEnable", 1);
registry.SetValue("ProxyServer", "127.0.0.1:8080");

Is going into the registry the best way to do this, or is there a more recommended approach? I'd like to avoid registry changes if there's an alternative solution.

score 22 · Accepted Answer · answered Oct 16 '08 at 15:34

22

This depends somewhat on your exact needs. If you are writing a C# app and simply want to set the default proxy settings that your app will use, use the class System.Net.GlobalProxySelection (http://msdn.microsoft.com/en-us/library/system.net.globalproxyselection.aspx). You can also set the proxy for any particular connection with System.Net.WebProxy (http://msdn.microsoft.com/en-us/library/system.net.webproxy.aspx).

If you actually want to update the proxy settings in the registry, I believe that you'll need to use P/Invoke to call the WinAPI function WinHttpSetDefaultProxyConfiguration (http://msdn.microsoft.com/en-us/library/aa384113.aspx).

answered Oct 16 '08 at 15:34

JSBձոգչ

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1. >If you actually want to update the proxy settings `in the registry`< If we need to change the registry entries, why do we need WinAPI? We can do it using C# like in the question. – claws Jan 07 '10 at 08:42
9

As far as I can tell, the WinHTTP proxy settings that `WinHttpSetDefaultProxyConfiguration` sets are **not** the same as the Internet Explorer settings. Did any of the 13 people who up-voted this actually *try* it? – Jonathon Reinhart Jul 31 '13 at 22:23

score 21 · Answer 2 · answered Dec 20 '10 at 20:20

from: http://social.msdn.microsoft.com/Forums/en/csharpgeneral/thread/19517edf-8348-438a-a3da-5fbe7a46b61a

Add these lines at the beginning of your code:

using System.Runtime.InteropServices; using Microsoft.Win32;

    [DllImport("wininet.dll")]
    public static extern bool InternetSetOption(IntPtr hInternet, int dwOption, IntPtr lpBuffer, int dwBufferLength);
    public const int INTERNET_OPTION_SETTINGS_CHANGED = 39;
    public const int INTERNET_OPTION_REFRESH = 37;
    bool settingsReturn, refreshReturn;

And imply the code:

        RegKey.SetValue("ProxyServer", YOURPROXY);
        RegKey.SetValue("ProxyEnable", 1);

        // These lines implement the Interface in the beginning of program 
        // They cause the OS to refresh the settings, causing IP to realy update
        settingsReturn = InternetSetOption(IntPtr.Zero, INTERNET_OPTION_SETTINGS_CHANGED, IntPtr.Zero, 0);
        refreshReturn = InternetSetOption(IntPtr.Zero, INTERNET_OPTION_REFRESH, IntPtr.Zero, 0);

score 14 · Answer 3 · edited Oct 27 '22 at 22:08

I wrote a 10 lines program to do that, feel free to try https://github.com/131/proxytoggle

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using Microsoft.Win32;

namespace ProxyToggle
{

    class Program
    {

        [DllImport("wininet.dll")]
        public static extern bool InternetSetOption(IntPtr hInternet, int dwOption, IntPtr lpBuffer, int dwBufferLength);
        public const int INTERNET_OPTION_SETTINGS_CHANGED = 39;
        public const int INTERNET_OPTION_REFRESH = 37;


        static void setProxy(string proxyhost, bool proxyEnabled)
        {
            const string userRoot = "HKEY_CURRENT_USER";
            const string subkey = "Software\\Microsoft\\Windows\\CurrentVersion\\Internet Settings";
            const string keyName = userRoot + "\\" + subkey;

            if(proxyhost.Length != 0)
               Registry.SetValue(keyName, "ProxyServer", proxyhost);
            Registry.SetValue(keyName, "ProxyEnable", proxyEnabled ? "1" : "0", RegistryValueKind.DWord);

            // These lines implement the Interface in the beginning of program 
            // They cause the OS to refresh the settings, causing IP to realy update
            InternetSetOption(IntPtr.Zero, INTERNET_OPTION_SETTINGS_CHANGED, IntPtr.Zero, 0);
            InternetSetOption(IntPtr.Zero, INTERNET_OPTION_REFRESH, IntPtr.Zero, 0);
        }

        static void Main(string[] args)
        {
            if (args.Length == 0)
            {
                setProxy("", false);
                return;
            }

            setProxy(args[0], true);
        }
    }
}

Your code is not working since a number 0 or 1 should be set to the ProxyEnable. You are setting a string and this is not working. I am fixing it — ehh, Mar 15 '17 at 10:14
My proxy server is getting set automatically by Group Policy or something. When I change it using your way by just executing the app it works just fine. When I'm trying to do the same from the windows service registry value gets set but immediately reverts to the policy default when I make any of these `InternetSetOption` calls. If I don't call InternetSetOption` - registry value changes but not the actual active proxy. Have no idea why. — rook, Apr 12 '17 at 22:14
Yep, can confirm, that Registry.SetValue(keyName, "ProxyEnable", proxyEnabled?"1": "0"); won't work, but Registry.SetValue(keyName, "ProxyEnable", proxyEnabled? 1: 0); works fine. (Values should be passed not as strings) — Vital, May 06 '17 at 11:40

score 6 · Answer 4 · answered Oct 13 '08 at 15:27

6

Check out this KB article specifically tagged at what you're trying to do.

http://support.microsoft.com/kb/226473

The short version is you want to use the InternetOpen, InternetSetOption API's to update the proxy settings.

answered Oct 13 '08 at 15:27

JaredPar

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The question was how to do this in C#. The KB article is not in C#. – Mark Good Mar 26 '11 at 13:46
@MarkGood Who cares? Not every API has been re-implemented in .NET. That's why PInvoke exists. – Jonathon Reinhart Jul 31 '13 at 19:14
@JaredPar the link you shared is no more exists on support.microsoft.com – Charan Ghate Mar 08 '18 at 13:40

score 3 · Answer 5 · answered Oct 22 '12 at 09:17

3

You can use this useful method existing since FW 2.0: (i've just discovered and i'm another man now...)

http://msdn.microsoft.com/en-us/library/system.net.webrequest.getsystemwebproxy.aspx

answered Oct 22 '12 at 09:17

Naim Raja Díaz

111
5

score -2 · Answer 6 · answered Jan 04 '12 at 08:50

-2

Quick Code example (from msdn):

WebProxy proxyObject = new WebProxy("http://proxyserver:80/",true);
WebRequest req = WebRequest.Create("http://www.contoso.com");
req.Proxy = proxyObject;

answered Jan 04 '12 at 08:50

Dave

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This doesn't change IE/WinINET's proxy settings. – EricLaw Oct 08 '13 at 21:43

Programmatically Set Browser Proxy Settings in C#

6 Answers6

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