delphi 关闭数字键盘|笨鱼技术网

Problem/Question/Abstract:

Using Delphi 5, I'm trying to setup a routine that would automatically turn off the NUMLOCK key when loaded. Assume that I am writing a standalone utility that could be loaded in the startup folder to do this function.

Answer:

Solve 1:

procedure SwitchToggleKey(Key: byte; State: boolean);
var
ks: TKeyboardState;
ScanCode: integer;
begin
if not key in [VK_CAPITAL, VK_NUMLOCK, VK_SCROLL, VK_INSERT] then
    exit;
if (key = VK_NUMLOCK) and (Win32Platform = VER_PLATFORM_WIN32_WINDOWS) then
begin
    GetKeyboardState(ks); {for Win95/98}
    if state then
      ks[key] := ks[key] or 1
    else
      ks[key] := ks[key] and 254;
    SetKeyboardState(ks);
end
else if odd(GetKeyState(key)) <> state then
begin
    ScanCode := MapVirtualKey(key, 0);
    keybd_event(key, ScanCode, {KEYEVENTF_EXTENDEDKEY} 0, 0);
    {Simulate a key release}
    keybd_event(key, ScanCode, {KEYEVENTF_EXTENDEDKEY or } KEYEVENTF_KEYUP, 0);
end;
end;

Note that not all controls "honor" the INSERT key, and others will only respond to the INSERT key while they have focus. I'm surprised that the Extended Key "attribute" works for the non-extended keys. Strangely enough, it works as well without KEYEVENTF_EXTENDEDKEY.

Solve 2:

procedure SimulateKeystroke(Key: byte; extra: DWORD);
begin
keybd_event(Key, extra, 0, 0);
keybd_event(Key, extra, KEYEVENTF_KEYUP, 0);
end;

function IsKeyToggled(key: byte): boolean;
var
state: word;
begin
state := windows.GetKeyState(key);
result := (state mod 128) = 1;
end;

function CapsLockStatus: boolean;
begin
result := IsKeyToggled(VK_CAPITAL);
end;

function NumLockStatus: boolean;
begin
result := IsKeyToggled(VK_NUMLOCK);
end;

procedure ToggleCapsLock;
begin
SimulateKeystroke(VK_CAPITAL, 0);
end;

procedure ToggleNumLock;
begin
SimulateKeystroke(VK_NUMLOCK, 0);
end;

procedure TForm1.btnOnClick(Sender: TObject);
begin
if not NumLockStatus then
ToggleNumLock;
end;

procedure TForm1.btnOffClick(Sender: TObject);
begin
if NumLockStatus then
ToggleNumLock;
end;

Solve 3:

I want to determine the state of the Num lock key on the keyboard and set it to on when my application begins or opens a specific form.

Note that the keyboard LED may not reflect the keys state correctly on all Windows platforms if you set it this way in code.

procedure SetLockKey(vcode: Integer; down: Boolean);
begin
if Odd(GetAsyncKeyState(vcode)) <> down then
begin
    keybd_event(vcode, MapVirtualkey(vcode, 0), KEYEVENTF_EXTENDEDKEY, 0);
    keybd_event(vcode, MapVirtualkey(vcode, 0), KEYEVENTF_EXTENDEDKEY or
      KEYEVENTF_KEYUP, 0);
end;
end;

SetLockKey(VK_NUMLOCK, True); {num lock down}