按键地勾子

以下是一个按键地勾子:
Intercepting The TAB and ENTER Keys
{the prototype for the new keyboard hook function}
function KeyboardHook(nCode: Integer; wParam: WPARAM;
lParam: LPARAM): LResult; stdcall;
var
Form1: TForm1;
WinHook: HHOOK; // a handle to the keyboard hook function
implementation
{$R *.DFM}
procedure TForm1.FormCreate(Sender: TObject);
begin
{install the keyboard hook function into the keyboard hook chain}
WinHook:=SetWindowsHookEx(WH_KEYBOARD, @KeyboardHook, 0, GetCurrentThreadID);
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
{remove the keyboard hook function from the keyboard hook chain}
UnhookWindowsHookEx(WinHook);
end;
function KeyboardHook(nCode: Integer; wParam: WPARAM; lParam: LPARAM): LResult;
begin
{if we can process the hook information...}
if (nCode>-1) then
{...was the TAB key pressed?}
if (wParam=VK_TAB) then
begin
{if so, output a beep sound}
MessageBeep(0);
{indicate that the message was processed}
Result := 1;
end
else
{...was the RETURN key pressed?}
if (wParam=VK_RETURN) then
begin
{if so, and if the key is on the up stroke, cause
the focus to move to the next control}
if ((lParam shr 31)=1) then
Form1.Perform(WM_NEXTDLGCTL, 0, 0);
{indicate that the message was processed}
Result := 1;
end
else
{otherwise, indicate that the message was not processed.}
Result := 0
else
{we must pass the hook information to the next hook in the chain}
Result := CallNextHookEx(WinHook, nCode, wParam, lParam);
end;
满意吗？分可别忘了！