I see some horrible solutions for this out on the web. Most involve setting the proxy for the entire machine and then toggling it back off. Here is a class that will allow you to set it ONLY FOR THE PROCESS that the control is hosted in. You could call it like this:
WinInetInterop.SetConnectionProxy(“localhost:8888”);
and then restore it to the default set in IE with this call:
// read the default settings for IE and restore these as the proxyWinInetInterop.RestoreSystemProxy();
Let me know if you thought this was useful!
Listing:
Using System;using System.Runtime.InteropServices;
namespace SetProxy{ public static class WinInetInterop { public static string applicationName;
[DllImport("wininet.dll", SetLastError = true, CharSet = CharSet.Auto)] private static extern IntPtr InternetOpen( string lpszAgent, int dwAccessType, string lpszProxyName, string lpszProxyBypass, int dwFlags);
[DllImport("wininet.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] private static extern bool InternetCloseHandle(IntPtr hInternet);
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)] private struct INTERNET_PER_CONN_OPTION_LIST { public int Size;
// The connection to be set. NULL means LAN. public System.IntPtr Connection;
public int OptionCount; public int OptionError;
// List of INTERNET_PER_CONN_OPTIONs. public System.IntPtr pOptions; } private enum INTERNET_OPTION { // Sets or retrieves an INTERNET_PER_CONN_OPTION_LIST structure that specifies // a list of options for a particular connection. INTERNET_OPTION_PER_CONNECTION_OPTION = 75,
// Notify the system that the registry settings have been changed so that // it verifies the settings on the next call to InternetConnect. INTERNET_OPTION_SETTINGS_CHANGED = 39,
// Causes the proxy data to be reread from the registry for a handle. INTERNET_OPTION_REFRESH = 37
}
private enum INTERNET_PER_CONN_OptionEnum { INTERNET_PER_CONN_FLAGS = 1, INTERNET_PER_CONN_PROXY_SERVER = 2, INTERNET_PER_CONN_PROXY_BYPASS = 3, INTERNET_PER_CONN_AUTOCONFIG_URL = 4, INTERNET_PER_CONN_AUTODISCOVERY_FLAGS = 5, INTERNET_PER_CONN_AUTOCONFIG_SECONDARY_URL = 6, INTERNET_PER_CONN_AUTOCONFIG_RELOAD_DELAY_MINS = 7, INTERNET_PER_CONN_AUTOCONFIG_LAST_DETECT_TIME = 8, INTERNET_PER_CONN_AUTOCONFIG_LAST_DETECT_URL = 9, INTERNET_PER_CONN_FLAGS_UI = 10 } private const int INTERNET_OPEN_TYPE_DIRECT = 1; // direct to net private const int INTERNET_OPEN_TYPE_PRECONFIG = 0; // read registry /// <summary> /// Constants used in INTERNET_PER_CONN_OPTON struct. /// </summary> private enum INTERNET_OPTION_PER_CONN_FLAGS { PROXY_TYPE_DIRECT = 0x00000001, // direct to net PROXY_TYPE_PROXY = 0x00000002, // via named proxy PROXY_TYPE_AUTO_PROXY_URL = 0x00000004, // autoproxy URL PROXY_TYPE_AUTO_DETECT = 0x00000008 // use autoproxy detection }
/// <summary> /// Used in INTERNET_PER_CONN_OPTION. /// When create a instance of OptionUnion, only one filed will be used. /// The StructLayout and FieldOffset attributes could help to decrease the struct size. /// </summary> [StructLayout(LayoutKind.Explicit)] private struct INTERNET_PER_CONN_OPTION_OptionUnion { // A value in INTERNET_OPTION_PER_CONN_FLAGS. [FieldOffset(0)] public int dwValue; [FieldOffset(0)] public System.IntPtr pszValue; [FieldOffset(0)] public System.Runtime.InteropServices.ComTypes.FILETIME ftValue; }
[StructLayout(LayoutKind.Sequential)] private struct INTERNET_PER_CONN_OPTION { // A value in INTERNET_PER_CONN_OptionEnum. public int dwOption; public INTERNET_PER_CONN_OPTION_OptionUnion Value; } /// <summary> /// Sets an Internet option. /// </summary> [DllImport("wininet.dll", CharSet = CharSet.Ansi, SetLastError = true)] private static extern bool InternetSetOption( IntPtr hInternet, INTERNET_OPTION dwOption, IntPtr lpBuffer, int lpdwBufferLength);
/// <summary> /// Queries an Internet option on the specified handle. The Handle will be always 0. /// </summary> [DllImport("wininet.dll", CharSet = CharSet.Ansi, SetLastError = true, EntryPoint = "InternetQueryOption")] private extern static bool InternetQueryOptionList( IntPtr Handle, INTERNET_OPTION OptionFlag, ref INTERNET_PER_CONN_OPTION_LIST OptionList, ref int size);
/// <summary> /// Set the proxy server for LAN connection. /// </summary> public static bool SetConnectionProxy(string proxyServer ) {
IntPtr hInternet = InternetOpen(applicationName,INTERNET_OPEN_TYPE_DIRECT, null, null, 0);
//// Create 3 options. //INTERNET_PER_CONN_OPTION[] Options = new INTERNET_PER_CONN_OPTION[3];
// Create 2 options. INTERNET_PER_CONN_OPTION[] Options = new INTERNET_PER_CONN_OPTION[2];
// Set PROXY flags. Options[0] = new INTERNET_PER_CONN_OPTION(); Options[0].dwOption = (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_FLAGS; Options[0].Value.dwValue = (int)INTERNET_OPTION_PER_CONN_FLAGS.PROXY_TYPE_PROXY;
// Set proxy name. Options[1] = new INTERNET_PER_CONN_OPTION(); Options[1].dwOption = (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_PROXY_SERVER; Options[1].Value.pszValue = Marshal.StringToHGlobalAnsi(proxyServer);
//// Set proxy bypass. //Options[2] = new INTERNET_PER_CONN_OPTION(); //Options[2].dwOption = // (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_PROXY_BYPASS; //Options[2].Value.pszValue = Marshal.StringToHGlobalAnsi("local");
//// Allocate a block of memory of the options. //System.IntPtr buffer = Marshal.AllocCoTaskMem(Marshal.SizeOf(Options[0]) // + Marshal.SizeOf(Options[1]) + Marshal.SizeOf(Options[2]));
// Allocate a block of memory of the options. System.IntPtr buffer = Marshal.AllocCoTaskMem(Marshal.SizeOf(Options[0]) + Marshal.SizeOf(Options[1]));
System.IntPtr current = buffer;
// Marshal data from a managed object to an unmanaged block of memory. for (int i = 0; i < Options.Length; i++) { Marshal.StructureToPtr(Options[i], current, false); current = (System.IntPtr)((int)current + Marshal.SizeOf(Options[i])); }
// Initialize a INTERNET_PER_CONN_OPTION_LIST instance. INTERNET_PER_CONN_OPTION_LIST option_list = new INTERNET_PER_CONN_OPTION_LIST();
// Point to the allocated memory. option_list.pOptions = buffer;
// Return the unmanaged size of an object in bytes. option_list.Size = Marshal.SizeOf(option_list);
// IntPtr.Zero means LAN connection. option_list.Connection = IntPtr.Zero;
option_list.OptionCount = Options.Length; option_list.OptionError = 0; int size = Marshal.SizeOf(option_list);
// Allocate memory for the INTERNET_PER_CONN_OPTION_LIST instance. IntPtr intptrStruct = Marshal.AllocCoTaskMem(size);
// Marshal data from a managed object to an unmanaged block of memory. Marshal.StructureToPtr(option_list, intptrStruct, true);
// Set internet settings. bool bReturn = InternetSetOption(hInternet, INTERNET_OPTION.INTERNET_OPTION_PER_CONNECTION_OPTION, intptrStruct, size);
// Free the allocated memory. Marshal.FreeCoTaskMem(buffer); Marshal.FreeCoTaskMem(intptrStruct); InternetCloseHandle(hInternet);
// Throw an exception if this operation failed. if (!bReturn) { throw new ApplicationException(" Set Internet Option Failed!"); }
return bReturn; }
/// <summary> /// Backup the current options for LAN connection. /// Make sure free the memory after restoration. /// </summary> private static INTERNET_PER_CONN_OPTION_LIST GetSystemProxy() {
// Query following options. INTERNET_PER_CONN_OPTION[] Options = new INTERNET_PER_CONN_OPTION[3];
Options[0] = new INTERNET_PER_CONN_OPTION(); Options[0].dwOption = (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_FLAGS; Options[1] = new INTERNET_PER_CONN_OPTION(); Options[1].dwOption = (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_PROXY_SERVER; Options[2] = new INTERNET_PER_CONN_OPTION(); Options[2].dwOption = (int)INTERNET_PER_CONN_OptionEnum.INTERNET_PER_CONN_PROXY_BYPASS;
// Allocate a block of memory of the options. System.IntPtr buffer = Marshal.AllocCoTaskMem(Marshal.SizeOf(Options[0]) + Marshal.SizeOf(Options[1]) + Marshal.SizeOf(Options[2]));
System.IntPtr current = (System.IntPtr)buffer;
// Initialize a INTERNET_PER_CONN_OPTION_LIST instance. INTERNET_PER_CONN_OPTION_LIST Request = new INTERNET_PER_CONN_OPTION_LIST();
// Point to the allocated memory. Request.pOptions = buffer;
Request.Size = Marshal.SizeOf(Request);
// IntPtr.Zero means LAN connection. Request.Connection = IntPtr.Zero;
Request.OptionCount = Options.Length; Request.OptionError = 0; int size = Marshal.SizeOf(Request);
// Query internet options. bool result = InternetQueryOptionList(IntPtr.Zero, INTERNET_OPTION.INTERNET_OPTION_PER_CONNECTION_OPTION, ref Request, ref size); if (!result) { throw new ApplicationException(" Set Internet Option Failed! "); }
return Request; }
/// <summary> /// Restore the options for LAN connection. /// </summary> /// <param name="request"></param> /// <returns></returns> public static bool RestoreSystemProxy() {
IntPtr hInternet = InternetOpen(applicationName, INTERNET_OPEN_TYPE_DIRECT, null, null, 0);
INTERNET_PER_CONN_OPTION_LIST request = GetSystemProxy(); int size = Marshal.SizeOf(request);
// Allocate memory. IntPtr intptrStruct = Marshal.AllocCoTaskMem(size);
// Convert structure to IntPtr Marshal.StructureToPtr(request, intptrStruct, true);
// Set internet options. bool bReturn = InternetSetOption(hInternet, INTERNET_OPTION.INTERNET_OPTION_PER_CONNECTION_OPTION, intptrStruct, size);
// Free the allocated memory. Marshal.FreeCoTaskMem(request.pOptions); Marshal.FreeCoTaskMem(intptrStruct);
if (!bReturn) { throw new ApplicationException(" Set Internet Option Failed! "); }
// Notify the system that the registry settings have been changed and cause // the proxy data to be reread from the registry for a handle. InternetSetOption(hInternet, INTERNET_OPTION.INTERNET_OPTION_SETTINGS_CHANGED, IntPtr.Zero, 0); InternetSetOption(hInternet, INTERNET_OPTION.INTERNET_OPTION_REFRESH, IntPtr.Zero, 0);
InternetCloseHandle(hInternet);
}}