private static bool IsAltTabKeyCombination(LowLevelKeyboardMessage keyboardMessage)
{
return keyboardMessage.VirtualKeyCode == (int) Keys.Tab
&& keyboardMessage.Flags == AltDown;
}
public static void KeyboardHook(LowLevelMessage evt, ref bool handled)
{
LowLevelKeyboardMessage kevt = evt as LowLevelKeyboardMessage;
// Prevent further code execution when the key stroke hasn't changed
if (_lastKeyboardMessage != null)
{
bool notchanged = (kevt.Message == _lastKeyboardMessage.Message)
&& (kevt.VirtualKeyCode == _lastKeyboardMessage.VirtualKeyCode)
&& (kevt.KeyboardEventFlags == _lastKeyboardMessage.KeyboardEventFlags)
&& (kevt.ExtraInfo == _lastKeyboardMessage.ExtraInfo);
if (notchanged)
return;
}
_lastKeyboardMessage = kevt;
// Get keyboard state
switch ((KeyboardMessage)kevt.Message)
{
case KeyboardMessage.WM_KEYDOWN:
case KeyboardMessage.WM_SYSKEYDOWN:
if (((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.LeftMenu) || ((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.RightMenu))
_isAltDown = true;
if (((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.LeftShift) || ((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.RightShift))
_isShiftDown = true;
if (((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.LeftControl) || ((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.RightControl))
_isControlDown = true;
break;
case KeyboardMessage.WM_KEYUP:
case KeyboardMessage.WM_SYSKEYUP:
if (((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.LeftMenu) || ((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.RightMenu))
_isAltDown = false;
if (((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.LeftShift) || ((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.RightShift))
_isShiftDown = false;
if (((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.LeftControl) || ((VirtualKeys)kevt.VirtualKeyCode == VirtualKeys.RightControl))
_isControlDown = false;
break;
}
}
