在XP/2K 下实现 Win+Ctrl+Del 等键的屏蔽的方法

在 Windows 98 下我们知道用 SystemParametersInfo(SPI_SETFASTTASKSWITCH, 1, @temp,
0); 来实现 Win+Ctrl+Del 的屏蔽，但这种方法在NT的操作系统下如 Windows XP / Windows
2000等就不行了，这里我给大家提供一个新的方法，采用钩子拦截的方式，来实现屏蔽系统按键。本示例附详细的源码与演示程序。


[b]源码与演示程序。



[/b]实现方法的代码如下：


{*******************************************************************************




XOtecExpress Visual Component Library [陆岛工作室]


Copyright (c) 2008 XOtec Studio. [PengJunli]




By: PengJunLi Build: 2008-06


E-mail: iinsnian@126.com XOtec@vip.QQ.com QQ:442801172




*******************************************************************************}




unit Unit2;




interface




uses


Windows, Messages, SysUtils, Variants, Classes;




type


tagKBDLLHOOKSTRUCT = packed record


vkCode: DWORD;


ScanCode: DWORD;


Flags: DWORD;


Time: DWORD;


dwExtraInfo: DWORD;


end;




KBDLLHOOKSTRUCT = tagKBDLLHOOKSTRUCT;


PKBDLLHOOKSTRUCT = ^KBDLLHOOKSTRUCT;




const


WH_KEYBOARD_LL = 13;


LLKHF_ALTDOWN = $20;




//采用钩子的方法屏蔽系统按键


function DisableTaskKeys(Disable: Boolean): Boolean;




implementation




var


hhkLowLevelKybd: HHOOK;




{ LowLevelKeyboardProc }




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 //nCode值为HC_ACTION时表示WParam和LParam参数包涵了按键消息


begin


//拦截按键消息并测试是否是Ctrl+Esc、Alt+Tab、和Alt+Esc功能键。


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 //屏蔽WIN按键


((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;




{ DisableTaskKeys }




function DisableTaskKeys(Disable: Boolean): Boolean;


begin


Result := False;




if (hhkLowLevelKybd = 0) and Disable then


begin


hhkLowLevelKybd :=SetWindowsHookExW(WH_KEYBOARD_LL, LowLevelKeyboardProc, Hinstance, 0); //设置钩子


Result := hhkLowLevelKybd<>0; // 返回设置成功


end else if not Disable and (hhkLowLevelKybd<>0) then


begin


if UnhookWindowsHookEx(hhkLowLevelKybd) then //卸载键盘钩子


begin


Result := True;


hhkLowLevelKybd := 0;


end;


end;


end;




end.