how to distinguish touch vs mouse event from SetWindowsHookEx in c#

Question

I have found a way to listen to the mouse event, but what I really want is the touch event not mouse. They seem to share the same code. Is there any way to tell if the event was

Answer 1

The lParam argument of your hookProc callback is a pointer to an MSLLHOOKSTRUCT. It contains a very poorly documented dwExtraInfo variable, which tells you whether it was generated from a touch.

If all of the bits in 0xFF515700 are set in dwExtraInfo, then the callback was invoked in response to a touch:

[StructLayout(LayoutKind.Sequential)]
struct MSLLHOOKSTRUCT
{
    public POINT pt;
    public uint mouseData;
    public uint flags;
    public uint time;
    public IntPtr dwExtraInfo;
}

const int TOUCH_FLAG = 0xFF515700;
bool IsTouch(IntPtr lParam)
{
    MSLLHOOKSTRUCT hookData = (MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, 
        typeof(MSLLHOOKSTRUCT));
    uint extraInfo = (uint)info.dwExtraInfo.ToInt32();
    if ((extraInfo & TOUCH_FLAG) == TOUCH_FLAG)
        return true;
    return false;
}