Служба Windows и Controls.pas

procedure TSvcus.ServiceCreate(Sender: TObject);
var
  NF:TDEV_BROADCAST_DEVICEINTERFACE;
begin
  NF.dbcc_size:=sizeof(TDEV_BROADCAST_DEVICEINTERFACE);
  NF.dbcc_devicetype:=DBT_DEVTYP_DEVICEINTERFACE;
 
 [COLOR="Red"] RegisterDeviceNotification(Handle,@NF,DEVICE_NOTIFY_ALL_INTERFACE_CLASSES);[/COLOR]
 
   allfiles_start:=TStringList.Create;
   allfiles_now:=TStringList.Create;
   newfiles:=TStringList.Create;
 
end;

uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
       Dialogs, StdCtrls,clipbrd,XPMan,shellapi,FileCtrl, DB, ADODB, DBTables, ExtCtrls, Buttons, setupapi,SvcMgr;

The following code is from the implementation of TTimer. It shows how the timer component’s constructor creates a hidden window to respond to Timer messages and how the destructor frees that window.
 
{TTimer implements a WndProc method that becomes the window procedure for the hidden window. }
procedure TTimer.WndProc(var Msg: TMessage);
 
begin
  with Msg do
    if Msg = WM_TIMER then { check for timer messages }
      try
        Timer; { this calls the OnTimer event handler }
      except
        Application.HandleException(Self);
      end
    else 
 { Any other messages are passed to DefWindowProc, which tells Windows to handle the message. Note that the first parameter, FWindowHandle, is the handle of the window receiving this message. It is obtained from the call to AllocateHWnd in the constructor. }
 
      Result := DefWindowProc(FWindowHandle, Msg, wParam, lParam);
 
end;
 
{ The TTimer constructor uses AllocateHWnd to create the window and save its handle. } 
constructor TTimer.Create(AOwner: TComponent);
 
begin
  inherited Create(AOwner);
  FEnabled := True;
  FInterval := 1000;
  FWindowHandle := AllocateHWnd(WndProc);
 
end;
 
{ The TTimer destructor calls DeallocateHWnd to free the hidden window. } 
destructor TTimer.Destroy;
 
begin
  FEnabled := False;
  UpdateTimer;
  DeallocateHWnd(FWindowHandle);
  inherited Destroy;
 
end;

type
  PDevBroadcastHdr  = ^DEV_BROADCAST_HDR;
  DEV_BROADCAST_HDR = packed record
    dbch_size: DWORD;
    dbch_devicetype: DWORD;
    dbch_reserved: DWORD;
  end;
 
  PDevBroadcastDeviceInterface  = ^DEV_BROADCAST_DEVICEINTERFACE;
  DEV_BROADCAST_DEVICEINTERFACE = record
    dbcc_size: DWORD;
    dbcc_devicetype: DWORD;
    dbcc_reserved: DWORD;
    dbcc_classguid: TGUID;
    dbcc_name: short;
  end;
//=============================================================
const
  GUID_DEVINTERFACE_USB_DEVICE: TGUID = '{A5DCBF10-6530-11D2-901F-00C04FB951ED}';
  DBT_DEVICEARRIVAL          = $8000;          // system detected a new device
  DBT_DEVICEREMOVECOMPLETE   = $8004;          // device is gone
  DBT_DEVTYP_DEVICEINTERFACE = $00000005;      // device interface class
  DEVICE_NOTIFY_ALL_INTERFACE_CLASSES = $00000004;
  DEVICE_NOTIFY_SERVICE_HANDLE = $00000001;
 
procedure TTESTSRVC.WMDeviceChange(var Msg: TMessage);
var
  devType: Integer; 
  Datos: PDevBroadcastHdr; 
begin 
  if (Msg.wParam = DBT_DEVICEARRIVAL) or (Msg.wParam = DBT_DEVICEREMOVECOMPLETE) then  
  begin
    Datos := PDevBroadcastHdr(Msg.lParam);
    devType := Datos^.dbch_devicetype;
    if devType = DBT_DEVTYP_DEVICEINTERFACE then
    begin // USB Device
      if Msg.wParam = DBT_DEVICEARRIVAL then
      begin
        showmessage('Устройство подключено');       // Усройство подключено
        //.....
      end
      else
      begin
        showmessage('Устройство ОТКЛЮЧЕНО');
        //.....
      end;
    end;
  end;
end;
 
 
procedure TTESTSRVC.ServiceStart(Sender: TService; var Started: Boolean);
var
  dbi: DEV_BROADCAST_DEVICEINTERFACE;
  Size: Integer;
  r: Pointer;
begin
  Size := SizeOf(DEV_BROADCAST_DEVICEINTERFACE);
  ZeroMemory(@dbi, Size);
  dbi.dbcc_size := Size;
  dbi.dbcc_devicetype := DBT_DEVTYP_DEVICEINTERFACE;
  dbi.dbcc_reserved := 0;
  dbi.dbcc_classguid  := GUID_DEVINTERFACE_USB_DEVICE;
  dbi.dbcc_name := 0;
 
 
  r := RegisterDeviceNotification(Handle, @dbi, DEVICE_NOTIFY_SERVICE_HANDLE);
  if not Assigned(r) then
   ShowMessage('Error Register Message');
 
 end;

hWnd := AllocateHWnd(..);

unit usbmonsvc;
 
interface
 
uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, SvcMgr, Dialogs;
 
type
  TSVCUS = class(TService)
    procedure ServiceStart(Sender: TService; var Started: Boolean);
  private
    { Private declarations }
   FhWnd : THandle;
   procedure NotifyWndProc(var Msg: TMessage);
  public
    function GetServiceController: TServiceController; override;
    { Public declarations }
  end;
 
var
  SVCUS: TSVCUS;
 
implementation
 
{$R *.DFM}
 
//++++++++++++++++++++++++++СЕРВИСНЫЕ++++++++++++++++++++++++++++++++++++++++
procedure ServiceController(CtrlCode: DWord); stdcall;
begin
  SVCUS.Controller(CtrlCode);
end;
 
function TSVCUS.GetServiceController: TServiceController;
begin
  Result := ServiceController;
end;
//++++++++++++++++++++++++++СЕРВИСНЫЕ КОНЕЦ++++++++++++++++++++++++++++++++++
 
procedure TSVCUS.NotifyWndProc(var Msg: TMessage);
begin
  case Msg.Msg of
         WM_DEVICECHANGE:
           begin
           Showmessage('Что то происходит!');
           end;
  else
     Msg.Result := DefWindowProc(FhWnd, Msg.Msg, Msg.wParam, Msg.lParam);
  end;
end;
 
procedure TSVCUS.ServiceStart(Sender: TService; var Started: Boolean);
begin
FhWnd := AllocateHWnd(NotifyWndProc);
end;
 
end.