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.

JSBձոգչ · Accepted Answer · 2008-10-16 15:34:34Z

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, 2008 at 15:34

JSBձոգչ

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2 Comments

claws Over a year ago

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.

Jonathon Reinhart Over a year ago

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?

chris · Accepted Answer · 2010-12-20 20:20:52Z

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);

Hasan Uddin · Accepted Answer · 2022-10-27 22:08:43Z

14

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);
        }
    }
}

edited Oct 27, 2022 at 22:08

Hasan Uddin

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answered Oct 9, 2014 at 7:52

131

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3 Comments

ehh Over a year ago

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

rook Over a year ago

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.

Vital Over a year ago

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)

JaredPar · Accepted Answer · 2008-10-13 15:27:06Z

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, 2008 at 15:27

JaredPar

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3 Comments

Mark Good Over a year ago

The question was how to do this in C#. The KB article is not in C#.

Jonathon Reinhart Over a year ago

@MarkGood Who cares? Not every API has been re-implemented in .NET. That's why PInvoke exists.

Charan Ghate Over a year ago

@JaredPar the link you shared is no more exists on support.microsoft.com

Naim Raja Díaz · Accepted Answer · 2012-10-22 09:17:46Z

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, 2012 at 9:17

Naim Raja Díaz

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Comments

Dave · Accepted Answer · 2012-01-04 08:50:06Z

-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 4, 2012 at 8:50

Dave

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1 Comment

EricLaw Over a year ago

This doesn't change IE/WinINET's proxy settings.

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