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Keyboard Lights

Posted on 2001-08-10
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Last Modified: 2010-04-06
I wonder how i can get the "Keyboard Ligths"
(NUM LOCK/CAPS LOCK/SCREEN LOCK) to all be turned on...
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Question by:TeChNiCh
11 Comments
 
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DragonSlayer earned 200 total points
ID: 6374690
procedure ToggleKey(VirtKey: Integer; SetOn: Boolean);
var
  IsToggledOn: Boolean;
begin
  IsToggledOn := (GetKeyState(VirtKey) and 1) = 1;
  if IsToggledOn <> SetOn then
  begin
    keybd_event(VirtKey, 0, 0, 0);
    keybd_event(VirtKey, 0, KEYEVENTF_KEYUP, 0);
  end;
end;


The above procedure will check if a key is toggled on/off.

To set CAPS LOCK to ON:

ToggleKey(VK_CAPITAL, True);
and to set it to OFF again:
ToggleKey(VK_CAPITAL, False);

NUM LOCK's virtual key is VK_NUMLOCK
SCROLL LOCK's virtual key is VK_SCROLL



DragonSlayer.
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LVL 1

Expert Comment

by:sundayboys
ID: 6374729
function IsNumLockOn: boolean;
var KeyState: TKeyboardState;
begin
GetKeyboardState(KeyState);
Result := (KeyState[VK_NUMLOCK] and 1) = 1;
end;

procedure NumLockOn;
var KeyState: TKeyboardState;
begin
GetKeyboardState(KeyState);
KeyState[VK_NUMLOCK] := $01;
SetKeyboardState(KeyState);
end;

procedure NumLockOff;
var KeyState: TKeyboardState;
begin
GetKeyboardState(KeyState);
KeyState[VK_NUMLOCK] := $00;
SetKeyboardState(KeyState);
end;

// these tips can use with other keys ie. VK_CAPITAL, VK_SCROLL

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LVL 14

Expert Comment

by:DragonSlayer
ID: 6374905
SundayBoys,

From the Win32 API help file:

Because the SetKeyboardState function alters the input state of the calling thread and not the global input state of the system, an application cannot use SetKeyboardState to set the NUM LOCK, CAPS LOCK, or SCROLL LOCK indicator lights on the keyboard.


DragonSlayer.
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Expert Comment

by:sundayboys
ID: 6374959
DragpmSlayer?F
  try my code,it can change NUMLOCK lights.my OS is win98se.
  Don't  always trust Microsoft!
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by:DragonSlayer
ID: 6374993
:)
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Expert Comment

by:sundayboys
ID: 6375071
:-)
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Expert Comment

by:robert_marquardt
ID: 6375078
I think the code does not only sets the numlock light but also the numlock state!
The problem is that Windows now has a virtual system keyboard and you cannot fiddle with the keyboard controller anymore. It may be that your oly keyboard is USB which is not controlled by the keyboard controller.
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Expert Comment

by:Madshi
ID: 6375230
We needed to control the LEDs (including the state) in win9x in our firm, too. We worked hard on that and finally found a method which works more or less reliable. But it works only in connection with our little keyboard driver.

We also tried the SetKeyboardState stuff, of course, but somehow it made problems. I don't remember exactly, what the problem was. I think, it was not reliable, on some keyboards it did work, on others it did not.

Regards, Madshi.
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LVL 1

Expert Comment

by:Dennis9
ID: 6377162
hi.
Something like this?


procedure TurnAllOn;
var
  keys: TKeyboardState;
begin
  GetKeyboardState( keys );
  keys[VK_NUMLOCK] := 1;  {Num Lock}
  keys[VK_CAPITAL] := 1;  {Caps Lock}
  keys[VK_SCROLL]  := 1;  {Scroll Lock}
  SetKeyboardState(keys);
end;

procedure TurnAllOff;
var
  keys: TKeyboardState;
begin
  GetKeyboardState( keys );
  keys[VK_NUMLOCK] := 0;  {Num Lock}
  keys[VK_CAPITAL] := 0;  {Caps Lock}
  keys[VK_SCROLL]  := 0;  {Scroll Lock}
  SetKeyboardState(keys);
end;


Dennis
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by:Netminder
ID: 7872453
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by:SpideyMod
ID: 8145016
Administrative Action - Force Accepted

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