Mega Code Archive
Programmatically Get and Set the State of the CapsLock and NumLock Keys (Delphi)
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Title: Programmatically Get and Set the State of the CapsLock and NumLock Keys (Delphi)
The VK_CAPITAL virtual key constant defines the Caps Lock key.
The VK_NUMLOCK constant defines the Num Lock key.
If you need to programmatically turn on or off the Caps Lock or Num Lock key, you can use the following procedure:
procedure ToggleNumLock;
var
KeyState: TKeyboardState;
begin
//note: Use VK_CAPITAL for Caps Lock
GetKeyboardState(KeyState) ;
//simulate key events (down + up)
if (KeyState[VK_NUMLOCK] = 0) then
begin
Keybd_Event(VK_NUMLOCK, 1, KEYEVENTF_EXTENDEDKEY or 0, 0) ;
Keybd_Event(VK_NUMLOCK, 1, KEYEVENTF_EXTENDEDKEY or KEYEVENTF_KEYUP, 0) ;
end
else
begin
Keybd_Event(VK_NUMLOCK, 0, KEYEVENTF_EXTENDEDKEY or 0, 0) ;
Keybd_Event(VK_NUMLOCK, 0, KEYEVENTF_EXTENDEDKEY or KEYEVENTF_KEYUP, 0) ;
end;
end;
Note: The keybd_event function synthesizes a keystroke. We call it two times to generate WM_KEYUP and WM_KEYDOWN messages.
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