unit uHook;


interface


uses
  Windows, Messages, SysUtils, Variants, Classes, Controls, Forms, Dialogs,
  StdCtrls;


type
  tagKBDLLHOOKSTRUCT = packed record
    vkCode: DWORD;
    scanCode: DWORD;
    flags: DWORD;
    time: DWORD;
    dwExtraInfo: DWORD;
  end;


  KBDLLHOOKSTRUCT = tagKBDLLHOOKSTRUCT;


  PKBDLLHOOKSTRUCT = ^KBDLLHOOKSTRUCT;


const
  WH_KEYBOARD_LL = 13;


const
  LLKHF_ALTDOWN = $20;


function LowLevelKeyboardProc(nCode: Integer; WParam: WPARAM; LParam: LPARAM): LRESULT; stdcall;


procedure hookstar;


procedure hookend;


var
  hhkLowLevelKybd: HHOOK;


implementation


function LowLevelKeyboardProc(nCode: Integer; WParam: WPARAM; LParam: LPARAM): LRESULT; stdcall;
var
  fEatKeystroke: BOOL;
  p: PKBDLLHOOKSTRUCT;
begin
  Result := 0;
  fEatKeystroke := FALSE;
  p := PKBDLLHOOKSTRUCT(lParam);
  if (nCode = HC_ACTION) then
  begin
    case wParam of
          WM_KEYDOWN, WM_SYSKEYDOWN, WM_KEYUP, WM_SYSKEYUP:fEatKeystroke:=
//    ((p.vkCode=VK_TAB) and ((p.flags and LLKHF_ALTDOWN) <> 0)) or
//    ((p.vkCode=VK_ESCAPE) and ((p.flags and LLKHF_ALTDOWN) <> 0))or
//    (p.vkCode=VK_Lwin) or
//    (p.vkCode=VK_Rwin) or
//    (p.vkCode=VK_apps) or
//    ((p.vkCode=VK_ESCAPE) and ((GetKeyState(VK_CONTROL) and $8000) <> 0)) or
    ((p.vkCode=VK_F4) and ((p.flags and LLKHF_ALTDOWN) <> 0))
//    or
//    ((p.vkCode=VK_SPACE) and ((p.flags and LLKHF_ALTDOWN) <> 0)) or
//    (((p.vkCode=VK_CONTROL) and (P.vkCode = LLKHF_ALTDOWN and p.flags) and (P.vkCode=VK_Delete)))
    end;
  end;
  if fEatKeystroke = True then
    Result := 1;
  if nCode <> 0 then
    Result := CallNextHookEx(0, nCode, wParam, lParam);
end;


procedure HookStar;
begin
  if hhkLowLevelKybd = 0 then
    hhkLowLevelKybd := SetWindowsHookExW(WH_KEYBOARD_LL, LowLevelKeyboardProc, Hinstance, 0);
end;


procedure HookEnd;
begin
  if (hhkLowLevelKybd <> 0) and UnhookWindowsHookEx(hhkLowLevelKybd) then
    hhkLowLevelKybd := 0;
end;


initialization
  hookstar;


finalization
  hookend;


end.