Question

How can I handle tilt left or tilt right mouse event in WPF?
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Answer 1

I figured out how to implement WndProc in WPF UserControl. UserControl must obtain a window pointer like by AppendWindow method in my example:

private static MyUserControl instanceWithFocus;

public void AppendWindow(Window window) {
    HwndSource source = HwndSource.FromHwnd(new WindowInteropHelper(window).Handle);
    source.AddHook(new HwndSourceHook(WndProc));
}

private static IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled) {
    switch (msg) {
        case Win32Messages.WM_MOUSEHWHEEL:
            MouseWheelTilt(wParam, lParam);
            handled = true;
            break;
        default:
            break;
    }
    return IntPtr.Zero;
}

private static void MouseWheelTilt(IntPtr wParam, IntPtr lParam) {
    Int32 tilt = (Int16)Utils.HIWORD(wParam);
    Int32 keys = Utils.LOWORD(wParam);
    Int32 x = Utils.LOWORD(lParam);
    Int32 y = Utils.HIWORD(lParam);

    // call an event on active instance of this object
    if (instanceWithFocus != null) {
        instanceWithFocus.MouseWheelTilt(tilt, keys, x, y);
    }
}

private void MouseWheelTilt(Int32 tilt, Int32 keys, Int32 x, Int32 y) {
    scrollViewer.ScrollToHorizontalOffset(scrollViewer.HorizontalOffset + tilt);
}

private void UserControl_MouseEnter(object sender, MouseEventArgs e) {
    instanceWithFocus = this;
}

private void UserControl_MouseLeave(object sender, MouseEventArgs e) {
    instanceWithFocus = null;
}

abstract class Win32Messages {
    public const int WM_MOUSEHWHEEL = 0x020E;
}

abstract class Utils {

    internal static Int32 HIWORD(IntPtr ptr) {
        Int32 val32 = ptr.ToInt32();
        return ((val32 >> 16) & 0xFFFF);
    }

    internal static Int32 LOWORD(IntPtr ptr) {
        Int32 val32 = ptr.ToInt32();
        return (val32 & 0xFFFF);
    }

}