library HOOK;

uses
  System.SysUtils,
  System.Classes,
  Vcl.Dialogs,
  Winapi.Windows,
  Winapi.Messages;

{$R *.res}

const
  HookMsg = WM_USER + $0125;
  ID_APP = 'APPHWND';
  ID_HOOK = 'HHOOKID';

//------------------------------------------------------------------------------
// CBTProc
//------------------------------------------------------------------------------
function CBTProc(Code: NativeInt; WParam: WPARAM; LParam: LPARAM): LRESULT; stdcall;
var
  AppWnd: HWND;
begin
  messagebeep(0);
  AppWnd := GetDesktopWindow();
  if Code > 0 then begin
    Result := 0;
    AppWnd := GetProp(AppWnd, ID_APP);
    PostMessage(AppWnd, HookMsg, wParam, Code);
  end else
    Result := CallNextHookEx(GetProp(AppWnd, ID_HOOK), Code, wParam, lParam)
end;

//------------------------------------------------------------------------------
// SetHook
//------------------------------------------------------------------------------
function SetHook(wnd: hwnd): boolean; export; stdcall;
var
  hwndDsk: HWND;
  HookID: HHOOK;
begin
  hwndDsk := GetDesktopWindow();
  SetProp(hwndDsk, ID_APP, wnd);
  HookID:= SetWindowsHookEx(WH_SHELL, @CBTProc, HInstance, 0);
  SetProp(hwndDsk, ID_HOOK, HookID);
  Result := HookID <> 0;
end;

//------------------------------------------------------------------------------
// UnSetHook
//------------------------------------------------------------------------------
procedure UnSetHook; export; stdcall;
var
  AppWnd: HWND;
  HookID: HHOOK;
begin
  AppWnd := GetDesktopWindow();
  HookID := GetProp(AppWnd, ID_HOOK);
  if HookID <> 0 then
    UnHookWindowsHookEx(HookID);
end;

exports
  SetHook, UnSetHook;

end.

//------------------------------------------------------------------------------
// ShellHookMessage
//------------------------------------------------------------------------------
const
  HSHELL_WINDOWCREATED = 1;
  HSHELL_WINDOWDESTROYED = 2;
  HSHELL_WINDOWACTIVATED = 32772;
  HSHELL_FLASH = 32774;

library ShellHook;

uses
  System.SysUtils,
  System.Classes,
  Winapi.Windows,
  Winapi.Messages;

{$R *.res}

const
  ID_HookHandle = 'ID_HookHandle';
  ID_AppWnd = 'ID_AppWnd';

var
  HookHandle: integer;
  AppWnd: integer;

  WM_WINDOWCREATED: Cardinal;
  WM_WINDOWDESTROYED: Cardinal;
  WM_WINDOWACTIVATED: Cardinal;

function HookProc(nCode: integer; wParam: WPARAM; lParam: LPARAM): LRESULT; stdcall;
var
  wnd: integer;
begin
  HookHandle := GetProp(GetDesktopWindow, ID_HookHandle);
  AppWnd := GetProp(GetDesktopWindow, ID_AppWnd);

  if (nCode < 0) then
  begin
    Exit;
    Result := CallNextHookEx(HookHandle, nCode, wParam, lParam);
  end;
  messagebeep(0);

  case nCode of
    HSHELL_WINDOWCREATED: SendMessage(AppWnd, WM_WINDOWCREATED, wParam, 0);
    HSHELL_WINDOWDESTROYED: SendMessage(AppWnd, WM_WINDOWDESTROYED, wParam, 0);
    HSHELL_WINDOWACTIVATED: SendMessage(AppWnd, WM_WINDOWACTIVATED, wParam, 0);
  end;

  //Передаём сообщение дальше по цепочке hook-ов
  Result := CallNextHookEx(HookHandle, nCode, wParam, lParam);
end;


procedure SetHook(wnd: integer); export; stdcall;
begin
  SetProp(GetDesktopWindow, ID_AppWnd, wnd);
  HookHandle := SetWindowsHookEx(WH_SHELL, @HookProc, HInstance, 0);
  SetProp(GetDesktopWindow, ID_HookHandle, HookHandle);

end;

procedure DellHook; export; stdcall;
begin
  HookHandle := GetProp(GetDesktopWindow, ID_HookHandle);
  UnHookWindowsHookEx(HookHandle);
end;

exports
  SetHook, DellHook;

begin
  WM_WINDOWCREATED := RegisterWindowMessage('ShellHook_WINDOWCREATED');
  WM_WINDOWDESTROYED := RegisterWindowMessage('ShellHook_WINDOWDESTROYED');
  WM_WINDOWACTIVATED := RegisterWindowMessage('ShellHook_WINDOWACTIVATED');
end.

unit MU;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, sMemo, sButton,
  Vcl.ExtCtrls, sPanel;

{для динамической загрузки функций из DLL}
type
  TSetHook = procedure(wnd: integer); stdcall;
  TDellHook = procedure; stdcall;

type
  TMF = class(TForm)
    Memo: TsMemo;
    sPanel1: TsPanel;
    Button1: TsButton;
    Button2: TsButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure FormCreate(Sender: TObject);
  private
    procedure WndProc(var Msg: TMessage); override;
  public
    { Public declarations }
  end;

var
  MF: TMF;
  WM_WINDOWCREATED: integer;
  WM_WINDOWDESTROYED: integer;
  WM_WINDOWACTIVATED: integer;

implementation

{$R *.dfm}

var
  ShellHookHandle: HWND = 0; {дескриптор загружаемой DLL}
  SetHook: TSetHook;
  DellHook: TDellHook;

procedure TMF.WndProc(var Msg: TMessage);
begin
  inherited;
  if Msg.Msg = WM_WINDOWCREATED then
    Memo.Lines.Add('WindowCreated: ' + Msg.wParam.ToString);
  if Msg.Msg = WM_WINDOWDESTROYED then
    Memo.Lines.Add('WindowDestroyed: ' + Msg.wParam.ToString);
  if Msg.Msg = WM_WINDOWACTIVATED then
    Memo.Lines.Add('WindowActivated: ' + Msg.wParam.ToString);
 end;

procedure TMF.Button1Click(Sender: TObject);
begin
  @SetHook := nil; // инициализируем переменную hook
  @DellHook := nil;
  ShellHookHandle := LoadLibrary(PChar('ShellHook.dll')); { загрузка DLL }
  if ShellHookHandle > HINSTANCE_ERROR then            { если всё без ошибок, то }
  begin
    @Sethook := GetProcAddress(ShellHookHandle, 'SetHook');     { получаем указатель на необходимую процедуру}
    @Dellhook := GetProcAddress(ShellHookHandle, 'DellHook');
    Sethook(Self.Handle);
  end else
  ShowMessage('Ошибка при загрузке DLL!');
end;

procedure TMF.Button2Click(Sender: TObject);
begin
  DellHook;
end;

procedure TMF.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  if ShellHookHandle <> 0 then
    FreeLibrary(ShellHookHandle); { при закрытии формы - освобождаем DLL }
end;

{ Регистрируем сообщения }
initialization
  WM_WINDOWCREATED := RegisterWindowMessage('ShellHook_WINDOWCREATED');
  WM_WINDOWDESTROYED := RegisterWindowMessage('ShellHook_WINDOWDESTROYED');
  WM_WINDOWACTIVATED := RegisterWindowMessage('ShellHook_WINDOWACTIVATED');
end.