// 低级键盘钩子回调函数
//
function LowLevelKeyboardFunc(nCode: Integer; w_Param: WPARAM;
l_Param: LPARAM): LRESULT; stdcall;
var
blEatKeystroke: Boolean;
p: PKBDLLHOOKSTRUCT;
begin
blEatKeystroke := False;
if nCode = HC_ACTION then
begin
case w_Param of
WM_KEYDOWN,
WM_SYSKEYDOWN,
WM_KEYUP,
WM_SYSKEYUP:
begin
p := PKBDLLHOOKSTRUCT(l_Param);
// 进行按键过滤
blEatKeystroke := (((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_ESCAPE) and
((GetKeyState(VK_CONTROL) and $8000) <> 0)) or
((p^.vkCode = VK_DELETE) and
((p^.flags and LLKHF_ALTDOWN) <> 0) and
((GetKeyState(VK_CONTROL) and $8000) <> 0)));
end;
end; // End of Case
end;
if blEatKeystroke then
begin
Result := 1; // 捕获这些组合键,按键消息由自己处理,必须返回 1
Hook.ShowHookInfo; // 显示一个窗口,你可以改为自己的处理代码
end
else
// 其他的按键,交由别的线程处理(过滤)
Result := CallNextHookEx(0, nCode, w_Param, l_Param);
end;
procedure TMainForm.AboutBtnClick(Sender: TObject);
begin
Application.MessageBox(
PChar('Windows NT 键盘钩子演示程序'#13#10#13#10'作者:Phoenix2000,2001年7月。'),
'关于本程序', 0);
end;
procedure TMainForm.FormCreate(Sender: TObject);
begin
hhkNTKeyboard := 0; // 钩子句柄初值
end;
procedure TMainForm.EnableBtnClick(Sender: TObject);
begin
// 挂上键盘钩子
//
hhkNTKeyboard := SetWindowsHookEx(WH_KEYBOARD_LL,
LowLevelKeyboardFunc,
HInstance, 0);
if hhkNTKeyboard <> 0 then
Application.MessageBox('系统键盘钩子已经启动了!', '信息', 64)
else
Application.MessageBox('无法启动系统键盘钩子!', '错误', 16);
end;
procedure TMainForm.DisableBtnClick(Sender: TObject);
begin
// 解除键盘钩子
//
if hhkNTKeyboard = 0 then
Application.MessageBox('系统键盘钩子已经被禁止了!', '警告', 48)
else
begin
UnhookWindowsHookEx(hhkNTKeyboard); // 卸载钩子
hhkNTKeyboard := 0;
Hook.CleanHookForm; // 此行代码与钩子无关,不要误解,是我自己的窗体清除
Application.MessageBox('成功卸载系统键盘钩子!', '信息', 64)
end;
end;
procedure TMainForm.ExitBtnClick(Sender: TObject);
begin
Close;
end;
procedure TMainForm.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
CanClose := (hhkNTKeyboard = 0);
if not CanClose then
Application.MessageBox('请先卸载系统键盘钩子,然后再退出本程序!', '警告', 48);
end;
procedure TMainForm.FormDestroy(Sender: TObject);
begin
if hhkNTKeyboard <> 0 then
begin
UnhookWindowsHookEx(hhkNTKeyboard);
hhkNTKeyboard := 0;
end;
Hook.CleanHookForm;
end;