Setting Internet Proxy in IE on active dial up or vpn connection in delphi

Question

I want to set proxy in action connection for IE with Delphi codes. I test this code:

Procedure SetProxy(const Server: String);
var
  Reg : TRegistry;
begin
  Reg := TRegistry.Create;
  Reg.OpenKey('Software\Microsoft\Windows\CurrentVersion\Internet Settings',False);
  Reg.WriteString('ProxyServer',Server);
  Reg.WriteBool('ProxyEnable',True);
  Reg.CloseKey;
  Reg.Free;
  InternetSetOption(0, INTERNET_OPTION_SETTINGS_CHANGED, 0, 0);
end;

But it is change only LAN Setting in IE Internet Option.

Anyone have a solution for that?

Additional: How can I retrieve Connection names list?

Answer 1

Amin, in your code you are setting the global proxy server. The setting for each connection is stored in this location HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections in a binary format which is not very well documented, so you must figure out the format and position to write the correct data.

Instead of the windows registry you can use the InternetSetOption function, check this sample application which update the proxy configuration for a particular connection.

program UpdateProxyApp;

{$APPTYPE CONSOLE}

uses
  WinInet,
  Windows,
  SysUtils;

type
INTERNET_PER_CONN_OPTION = record
    dwOption: DWORD;
    Value: record
    case Integer of
    1: (dwValue: DWORD);
    2: (pszValue: PAnsiChar);
    3: (ftValue: TFileTime);
    end;
end;

LPINTERNET_PER_CONN_OPTION = ^INTERNET_PER_CONN_OPTION;
INTERNET_PER_CONN_OPTION_LIST = record
  dwSize: DWORD;
  pszConnection: LPTSTR;
  dwOptionCount: DWORD;
  dwOptionError: DWORD;
  pOptions: LPINTERNET_PER_CONN_OPTION;
end;

const
 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;
 PROXY_TYPE_DIRECT = $00000001; 
 PROXY_TYPE_PROXY = $00000002; 
 PROXY_TYPE_AUTO_PROXY_URL = $00000004; 
 PROXY_TYPE_AUTO_DETECT = $00000008; 
 INTERNET_OPTION_REFRESH = 37;
 INTERNET_OPTION_PER_CONNECTION_OPTION = 75;
 INTERNET_OPTION_SETTINGS_CHANGED = 39;

function SetConnectionProxy(const conn_name, proxy_addr : AnsiString) : Boolean;
var
    list     : INTERNET_PER_CONN_OPTION_LIST;
    dwBufSize: DWORD;
    Options  : array[0..2] of INTERNET_PER_CONN_OPTION;
begin
    dwBufSize   := SizeOf(list);
    list.dwSize := dwBufSize;
    list.pszConnection := PAnsiChar(conn_name);
    list.dwOptionCount := 3;
    list.pOptions      := @Options;

    // Set the flags
    Options[0].dwOption      := INTERNET_PER_CONN_FLAGS;
    Options[0].Value.dwValue := PROXY_TYPE_DIRECT OR PROXY_TYPE_PROXY;
    // Set proxy name
    Options[1].dwOption      := INTERNET_PER_CONN_PROXY_SERVER;
    Options[1].Value.pszValue:= PAnsiChar(proxy_addr);
    // Set proxy override .
    Options[2].dwOption      := INTERNET_PER_CONN_PROXY_BYPASS;
    Options[2].Value.pszValue:= PAnsiChar('local');

    // Set the new settings
    Result := InternetSetOption(nil, INTERNET_OPTION_PER_CONNECTION_OPTION, @list, dwBufSize);
    InternetSetOption(nil, INTERNET_OPTION_SETTINGS_CHANGED, nil, 0);
    InternetSetOption(nil, INTERNET_OPTION_REFRESH , nil, 0);
end;


begin
  try
     Writeln(Format('Settings updated %s',[BoolToStr(SetConnectionProxy('Your connection Name', '192.168.15.15:80'),True)]));
  except
    on E:Exception do
      Writeln(E.Classname, ': ', E.Message);
  end;
  Readln;
end.