[SOLVED] Keyboard hook
lazarus / 21-General

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pcurtis · 2021-05-20 11:48

I use the following code to hook the keyboard.

How can I make it "eat" the keypress?

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i unit
Unit1; {$mode delphi}{$H+} interface uses  Classes, SysUtils, Forms,
Controls, Graphics, Dialogs, ExtCtrls,  Windows, LCLType, Menus,
StdCtrls, ComCtrls, MyTimer, myled, MMSystem; type   { TForm1 }  
TForm1 = class(TForm)    Label1: TLabel;    Label2: TLabel;    Label3:
TLabel;    Label4: TLabel;    TrackBar1: TTrackBar;    procedure
FormCreate(Sender: TObject);    procedure FormDestroy(Sender:
TObject);  private    function Start: boolean;    function Stop:
Boolean;    function IsStarted: Boolean;  public   end; var  Form1:
TForm1;  llKeyboardHook: HHOOK = 0;  AHandle :
HWND; implementation {$R *.lfm} procedure SendKey(Wnd, VK :
Cardinal);begin  ShowWindow(Wnd, SW_SHOW); 
SetForegroundWindow(Wnd);   keybd_event(VK,0,0,0); 
keybd_event(VK,0,KEYEVENTF_KEYUP,0);end; function
LowLevelKeyboardHook(nCode: Integer; wParam: WPARAM; lParam: LPARAM):
HRESULT; stdcall;type  PKBDLLHOOKSTRUCT = ^TKBDLLHOOKSTRUCT; 
TKBDLLHOOKSTRUCT = packed record    vkCode: DWORD;    scanCode:
DWORD;    flags: DWORD;    time: DWORD;    dwExtraInfo: DWORD;   
AHandle : HWND;  end;var  pkbhs: PKBDLLHOOKSTRUCT;  bPASSON :
boolean;begin  bPASSON := true;  pkbhs :=
PKBDLLHOOKSTRUCT(Pointer(lParam));  Form1.Label2.Caption :=
pkbhs^.vkCode.ToString;  Form1.Label4.Caption :=
pkbhs^.flags.ToString;     if ((pkbhs^.vkCode = 109)) then  //-     
begin        Form1.TrackBar1.Position := Form1.TrackBar1.Position -
1;         bPASSON := False;      end;   if ((pkbhs^.vkCode = 107))
then   //+    begin      Form1.TrackBar1.Position :=
Form1.TrackBar1.Position + 1;      bPASSON := False;    end;   Result
:= CallNextHookEx(llKeyboardHook, 0, wParam, lParam);end; { TForm1
} function TForm1.Start: boolean;const  WH_KEYBOARD_LL = 13;begin  if
llKeyboardHook = 0 then    llKeyboardHook :=
SetWindowsHookEx(WH_KEYBOARD_LL, @LowLevelKeyboardHook, HInstance,
0);  Result := (llKeyboardHook <> 0)end; function TForm1.Stop:
Boolean;begin  Result := False;  if (llKeyboardHook <> 0) and
UnhookWindowsHookEx(llKeyboardHook) then  begin    llKeyboardHook :=
0;    Result := True;  end;end; function TForm1.IsStarted:
Boolean;begin  Result := (llKeyboardHook <> 0)end; procedure
TForm1.FormCreate(Sender: TObject);begin  if not Start then   
MessageDlg('Cannot start the hook!', mtError, [mbOk], 0); 
Label2.Caption := '0';  Label4.Caption := '0';end; procedure
TForm1.FormDestroy(Sender: TObject);begin  if IsStarted then   
Stop;end; end.

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balazsszekely · 2021-05-20 11:54

Like this:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i if EatMe
then   Result := -1else  Result := CallNextHookEx(llKeyboardHook, 0,
wParam, lParam);

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pcurtis · 2021-05-20 13:43

Thanks. Works perfectly.