InterceptKeys()
{
keyStream = Observable.Create <InterceptKeyEventArgs>(observer =>
{
Debug.Write("Subscribed to keys");
IntPtr hookId = IntPtr.Zero;
// Need to hold onto this callback, otherwise it will get GC'd as it is an unmanged callback
callback = (nCode, wParam, lParam) =>
{
if (nCode >= 0)
{
var eventArgs = CreateEventArgs(wParam, lParam);
observer.OnNext(eventArgs);
if (eventArgs.Handled)
{
return((IntPtr)1);
}
}
// ReSharper disable once AccessToModifiedClosure
return(Win32Methods.CallNextHookEx(hookId, nCode, wParam, lParam));
};
hookId = SetHook(callback);
return(Disposable.Create(() =>
{
Debug.Write("Unsubscribed from keys");
Win32Methods.UnhookWindowsHookEx(hookId);
callback = null;
}));
})
.Publish().RefCount();
}
IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
{
if (nCode >= 0)
{
bool alt = (Control.ModifierKeys & Keys.Alt) != 0;
bool control = (Control.ModifierKeys & Keys.Control) != 0;
bool shift = (Control.ModifierKeys & Keys.Shift) != 0;
bool keyDown = wParam == (IntPtr)Win32Methods.WM_KEYDOWN;
bool keyUp = wParam == (IntPtr)Win32Methods.WM_KEYUP;
int vkCode = Marshal.ReadInt32(lParam);
var key = (Keys)vkCode;
//http://msdn.microsoft.com/en-us/library/windows/desktop/ms646286(v=vs.85).aspx
if (key != Keys.RMenu && key != Keys.LMenu && wParam == (IntPtr)Win32Methods.WM_SYSKEYDOWN)
{
alt = true;
keyDown = true;
}
if (key != Keys.RMenu && key != Keys.LMenu && wParam == (IntPtr)Win32Methods.WM_SYSKEYUP)
{
alt = true;
keyUp = true;
}
var interceptKeyEventArgs = new InterceptKeyEventArgs(
key,
keyDown ?
KeyDirection.Down: keyUp
? KeyDirection.Up: KeyDirection.Unknown,
alt, control, shift);
subject.OnNext(interceptKeyEventArgs);
Debug.Write(key);
if (interceptKeyEventArgs.Handled)
{
Debug.WriteLine(" handled");
return((IntPtr)1); //handled
}
}
return(Win32Methods.CallNextHookEx(hookId, nCode, wParam, lParam));
}