/****************************************************************************************************************
Simple example how to inhibit special windows keys in our programs.
Traduced from the article:
http://msdn.microsoft.com/msdnmag/issues/0700/win32/
This code only works in Win NT, Win 2000 and so on.
It doesn't work  in Windows 98
****************************************************************************************************************/

/* Some needed defines */
DEFINE LLKHF_ALTDOWN = 0x20
DEFINE WH_KEYBOARD_LL = 13
STRUCT KBDLLHOOKSTRUCT ALIGN 1
    MEMBER vkCode AS DWORD
    MEMBER scanCode AS DWORD
    MEMBER flags AS DWORD
    MEMBER time AS DWORD
    MEMBER dwExtraInfo AS DWORD

/* Function hooking the special keys */
FUNCTION LowLevelKeyboardProc(nCode AS INT,wParam AS DWORD,lParam AS DWORD) AS LONG
// By returning a non-zero value from the hook procedure, the
 // message does not get passed to the target window
LOCAL pkbhs AS KBDLLHOOKSTRUCT
LOCAL bControlKeyDown := FALSE AS LOGIC
LOCAL tcontrol AS DWORD

	
	IF nCode == HC_ACTION
		IF wParam = WM_KEYDOWN .or. wParam = WM_SYSKEYDOWN .OR. wParam = WM_KEYUP .OR.;
			wParam = WM_SYSKEYUP

			pkbhs := PTR(_CAST, lParam)
		
		        tcontrol := GetKeyState(VK_CONTROL)
		        bControlKeyDown :=	(pkbhs.vkCode = VK_TAB .AND. _And(pkbhs.flags,LLKHF_ALTDOWN)!= 0 ) .OR.;
            				(pkbhs.vkCode = VK_ESCAPE .AND. _And(pkbhs.flags,LLKHF_ALTDOWN)!= 0 ) .OR. ;
            					(pkbhs.vkCode = VK_ESCAPE .AND. _And(tcontrol,0x8000) != 0) .OR.;
            					(pkbhs.vkCode = VK_LWIN) .OR.;
            					(pkbhs.vkCode = VK_RWIN)

           	IF bControlKeyDown
           		RETURN 1
           	ENDIF
		ENDIF
	ENDIF
		
RETURN CallNextHookEx (NULL, nCode, wParam, lParam)

METHOD Start() CLASS App
	LOCAL oWindow AS StandardSDIWindow

// Install the low-level keyboard & mouse hooks
LOCAL ptrfunc AS PTR  // ptr to function
LOCAL hhkLowLevelKybd AS PTR  // ptr to the hook thread
// install the function thread
ptrfunc := @LowLevelKeyboardProc()
hhkLowLevelKybd  := SetWindowsHookEx(WH_KEYBOARD_LL, ptrfunc, SELF:Handle(), 0)

	

	oWindow := StandardSDIWindow{SELF}
	oWindow:Caption := "Example Hook"
	// Make shell size same as data window
	oWindow:Size := Dimension{595, 425}
	oWindow:Show(SHOWNORMAL)
	
	SELF:Exec()

/* Here we have to free the resources */
METHOD QueryClose(oE)
	SUPER:QueryClose(oE)

	// free the resources (and the special keys)
	UnHookWindowsHookEx(hhkLowLevelKybd)
RETURN TRUE