There are two more functions that can toggle keyboard state but each of them has some specific limitations like SendInput does. In this article, you will find all possible variants with their descriptions and limitations and a simple solution for toggling these keys avoiding compatibility problems.
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// MfcxStatusBar.cpp : implementation file
// Copyright(c) Armen Hakobyan 2002
// mailto:armenh@cit.am
#include "stdafx.h"
#include "StatusBarEx.h"
#include <WinAble.h>
// CStatusBarEx
#define ID_TIMER_TIME 0x0001L
IMPLEMENT_DYNAMIC(CStatusBarEx, CStatusBar)
CStatusBarEx::CStatusBarEx()
{
}
CStatusBarEx::~CStatusBarEx()
{
}
BEGIN_MESSAGE_MAP(CStatusBarEx, CStatusBar)
ON_NOTIFY_REFLECT(NM_DBLCLK, OnNMDblclk)
END_MESSAGE_MAP()
// CStatusBarEx message handlers
void CStatusBarEx::OnNMDblclk(NMHDR* pNMHDR, LRESULT *pResult)
{
NMMOUSE* pNMMOUSE = (NMMOUSE*)pNMHDR;
INT nInd = GetItemID((int)pNMMOUSE->dwItemSpec);
if((nInd >= ID_INDICATOR_CAPS) &&
(nInd <= ID_INDICATOR_OVR))
{
UINT nVirtKey = 0;
switch(nInd)
{
case ID_INDICATOR_CAPS: nVirtKey = VK_CAPITAL; break;
case ID_INDICATOR_NUM: nVirtKey = VK_NUMLOCK; break;
case ID_INDICATOR_SCRL: nVirtKey = VK_SCROLL; break;
case ID_INDICATOR_OVR: nVirtKey = VK_INSERT; break;
}
ASSERT(nVirtKey >= 1 && nVirtKey<= 254);
DWORD dwVersion = ::GetVersion();
// Windows NT/2000/XP: The keybd_event function can toggle the
// NUM LOCK, CAPS LOCK, and SCROLL LOCK keys.
if( dwVersion < 0x80000000) // Win NT
{
::keybd_event( nVirtKey, 0x45, KEYEVENTF_EXTENDEDKEY, 0 );
::keybd_event( nVirtKey, 0x45, KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP, 0 );
}
else
{
// Windows 95/98/Me: The keybd_event function can toggle only the
// CAPS LOCK and SCROLL LOCK keys. It cannot toggle the NUM LOCK key.
// We can do this with SendInput but it requires
// Windows NT 4.0 SP3 and later or Windows 98 and later.
DWORD dwMin = (DWORD)(HIBYTE(LOWORD(dwVersion)));
if(dwMin >= 10) // Windows 98 and later
{
INPUT input[2];
::ZeroMemory(input, sizeof(input));
input[0].type = input[1].type = INPUT_KEYBOARD;
input[0].ki.wVk = input[1].ki.wVk = nVirtKey;
input[1].ki.dwFlags = KEYEVENTF_KEYUP; // THIS IS IMPORTANT
::SendInput(2, input, sizeof(INPUT));
}
else // Windows 95
{
// 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 (or the Japanese KANA) indicator lights
// on the keyboard.
BYTE byKeybState[256];
::GetKeyboardState(byKeybState);
byKeybState[nVirtKey] = !(BOOL)::GetKeyState(nVirtKey);
::SetKeyboardState(byKeybState);
}
}
::Beep(500, 100);
}
else
{
CWnd* pWnd = GetParent();
if(pWnd != NULL)
{
//TODO: SendNotifyMessage;
}
}
*pResult = 0;
}
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