uses UrlMon, WinInet,registry;

 //设置代理

function ChangeProxy(const Proxy,ByPass: string; const bEnabled: boolean = True): boolean;

var

  reg: Tregistry;

  info: INTERNET_PROXY_INFO;

  Fproxy: string;

begin

  Result := False;

  //FProxy :=Format('%s:%s',[Proxy,Port]);

  Fproxy := Proxy;

  reg :=Tregistry.Create;

  try

    reg.RootKey :=HKEY_CURRENT_USER;

    if reg.OpenKey('\Software\Microsoft\Windows\CurrentVersion\Internet Settings', True) then

    begin

      reg.Writestring('ProxyServer', Fproxy);

      reg.WriteInteger('ProxyEnable', integer(bEnabled));

      info.dwAccessType :=INTERNET_OPEN_TYPE_PROXY;

      info.lpszProxy :=pansichar(proxy);

      info.lpszProxyBypass :=pansichar(ByPass);

      InternetSetOption(nil, INTERNET_OPTION_PROXY, @info, SizeOf(Info));

      InternetSetOption(nil, INTERNET_OPTION_SETTINGS_CHANGED, nil, 0);

      Result:=True;

    end

  finally

    reg.CloseKey;

    reg.free;

  end;

end;

{调用：

//设置代理

ChangeProxy('192.168.1.2:8080','1',true);

//取消代理

ChangeProxy('192.168.1.2:8080','1',False);

}