unit UntHook;

interface   
    
uses   
Windows, Messages, SysUtils, Variants, Classes, Dialogs, StdCtrls;

{按鍵消息的結(jié)構(gòu)，Delphi中沒(méi)有。  注意：這個(gè)結(jié)構(gòu)在Windows   NT   4   sp3以上系統(tǒng) 中才能使用}
type
  tagKBDLLHOOKSTRUCT = packed   record
  vkCode:   DWORD;    //虛擬鍵值
  scanCode:   DWORD;  //掃描碼值（沒(méi)有用過(guò)）
  {一些擴(kuò)展標(biāo)志，這個(gè)值比較麻煩，MSDN上說(shuō)得也不太明白，但是
  根據(jù)這個(gè)程序，這個(gè)標(biāo)志值的第六位數(shù)（二進(jìn)制）為1時(shí)ALT鍵按下為0相反。}

  flags:   DWORD;
  time:   DWORD;      //消息時(shí)間戳
  dwExtraInfo: DWORD; //和消息相關(guān)的擴(kuò)展信息
end;

KBDLLHOOKSTRUCT = tagKBDLLHOOKSTRUCT;
PKBDLLHOOKSTRUCT = ^KBDLLHOOKSTRUCT;
    
//這個(gè)是低級(jí)鍵盤鉤子的索引值，Delphi中沒(méi)有，必須自己定義   
const   WH_KEYBOARD_LL = 13;   
//定義一個(gè)常量好和上面哪個(gè)結(jié)構(gòu)中的flags比較而得出ALT鍵是否按下   
const   LLKHF_ALTDOWN = $20;

//----聲明各個(gè)函數(shù)-------------
function   LowLevelKeyboardProc(nCode: Integer; WParam: WPARAM;LParam: LPARAM):LRESULT; stdcall;
procedure   hookstar;   //設(shè)置鉤子
procedure   hookend;

var   
hhkLowLevelKybd:   HHOOK;

implementation   
{   
功能：低級(jí)鍵盤鉤子的回調(diào)函數(shù)，在里面過(guò)濾消息   
參數(shù)：nCode   是Hook的標(biāo)志   
WParam   表示消息的類型   
LParam   是一個(gè)指向我們?cè)谏厦娑x的哪個(gè)結(jié)構(gòu)KBDLLHOOKSTRUCT的指針   
返回值:如果不是0的話windows就把這個(gè)消息丟掉，程序就不會(huì)再收到這個(gè)消息了。   
}   
function LowLevelKeyboardProc(nCode: Integer; WParam: WPARAM; LParam: LPARAM):LRESULT; stdcall;   
var   
  fEatKeystroke: BOOL;
  p: PKBDLLHOOKSTRUCT;
begin   
  Result := 0;
  fEatKeystroke := FALSE;
  p := PKBDLLHOOKSTRUCT   (lParam);
  //nCode值為HC_ACTION時(shí)表示W(wǎng)Param和LParam參數(shù)包涵了按鍵消息
  if (nCode = HC_ACTION) then
  begin
    //攔截按鍵消息并測(cè)試是否是Ctrl+Esc、Alt+Tab、和Alt+Esc功能鍵。
    case   wParam   of
    WM_KEYDOWN,
    WM_SYSKEYDOWN,
    WM_KEYUP,
    WM_SYSKEYUP:
    fEatKeystroke :=
    ((p.vkCode = VK_TAB) and ((p.flags and LLKHF_ALTDOWN) <> 0)) or //   Alt+Tab
    ((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   //上面是屏蔽WIN按鍵
    ((p.vkCode = VK_CONTROL) and (P.vkCode = LLKHF_ALTDOWN) and (P.vkCode = VK_Delete))   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)))   //AND   (p.flags = true)   ;
    end;
  end;

  if fEatKeystroke = True then
    Result := 1;

  if nCode <> 0 then
    Result := CallNextHookEx(0, nCode, wParam, lParam);
end;

procedure   hookstar;   //設(shè)置鉤子   
begin   
  //設(shè)置鍵盤鉤子
  if   hhkLowLevelKybd = 0   then
  begin
    hhkLowLevelKybd := SetWindowsHookExW(WH_KEYBOARD_LL, LowLevelKeyboardProc, Hinstance, 0);
    if   hhkLowLevelKybd <> 0   then
      //MessageBox(0, '鍵盤鉤子設(shè)置成功！', '提示', MB_OK)
    else
      //  MessageBox(0, '鍵盤鉤子設(shè)置失敗！', '提示', MB_OK);
    end
  else
      //MessageBox(Handle, '鍵盤鉤子已設(shè)置！', '提示', MB_OK);
end;

procedure   hookend;//卸載鍵盤鉤子   
begin   
  if   hhkLowLevelKybd <> 0   then
  if   UnhookWindowsHookEx(hhkLowLevelKybd) <> False   then
  begin
    //MessageBox(0, '系統(tǒng)熱鍵恢復(fù)使用！', '提示', MB_OK);
    hhkLowLevelKybd := 0;
  end
  else
    //MessageBox(Handle, '鍵盤鉤子卸載失敗！', '提示', MB_OK)
  else
    //MessageBox(Handle, '沒(méi)有發(fā)現(xiàn)鍵盤鉤子！', '提示', MB_OK);
end;


end.