Установка ловушки для клавиатуры

Code:

unit Unit1;

interface

uses

  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;

type

  TForm1 = class(TForm)

    but_StartHook: TButton;

    but_StopHook: TButton;

    label1: TLabel;

    Memo1: TMemo;

    procedure but_StartHookClick(Sender: TObject);

    procedure but_StopHookClick(Sender: TObject);

  private

    { Private declarations }

    hLib2: THandle;

    DllStr1: string;

    procedure DllMessage(var Msg: TMessage); message WM_USER + 1678;

  public

    { Public declarations }

  end;

var

  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.DllMessage(var Msg: TMessage);

begin

  if (Msg.wParam = 8) or (Msg.wParam = 13) then Exit;

  {the 8 is the Backspace and the 13 if the Enter key, You'll need to

do some special handleing for a string}

  DllStr1 := DllStr1 + Chr(Msg.wParam);

  label1.Caption := DllStr1;

end;

procedure TForm1.but_StartHookClick(Sender: TObject);

type

  TStartHook = function(MemoHandle, AppHandle: HWND): Byte;

var

  StartHook1: TStartHook;

  SHresult: Byte;

begin

  hLib2 := LoadLibrary('HookLib.dll');

  @StartHook1 := GetProcAddress(hLib2, 'StartHook');

  if @StartHook1 = nil then Exit;

  SHresult := StartHook1(Memo1.Handle, Handle);

  if SHresult = 0 then ShowMessage('the Key Hook was Started, good');

  if SHresult = 1 then ShowMessage('the Key Hook was already Started');

  if SHresult = 2 then ShowMessage('the Key Hook can NOT be Started, bad');

  if SHresult = 4 then ShowMessage('MemoHandle is incorrect');

end;

procedure TForm1.but_StopHookClick(Sender: TObject);

type

  TStopHook = function: Boolean;

var

  StopHook1: TStopHook;

  hLib21: THandle;

begin

  @StopHook1 := GetProcAddress(hLib2, 'StopHook');

  if @StopHook1 = nil then

  begin

    ShowMessage('Stop Hook DLL Mem Addy not found');

    Exit;

  end;

  if StopHook1 then

    ShowMessage('Hook was stoped');

  FreeLibrary(hLib2);

  {for some reason in Win XP you need to call FreeLibrary twice

maybe because you get 2 functions from the DLL? ?}

  FreeLibrary(hLib2);

end;

end.