Question

I am implementing the solution described here in a MVVM project: http://nui.joshland.org/2010/04/why-wont-wpf-controls-work-with-touch.html

But the problem is that if I implement the TouchDown and TouchUp event handlers in the UserControl in my XAML then I run into a problem where other GroupView cannot get the Window Messages for flicks anymore — OR flicks are not able to be processed so their associated window message are never sent.

The top-down structure of the views is:
ButtonsView — has Touch event handlers
GroupView — has Mouse event handlers and the Flicks event handlers

I’m using this in the code-behind to hook the flicks and handle them:

    private void UserControl_Loaded(object sender, RoutedEventArgs e)
    {
        HwndSource source = PresentationSource.FromVisual(this) as HwndSource;
        source.AddHook(WndProc);
    }

    private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
    {
        if (msg == Flicks.WM_TABLET_FLICK)
        {
            Flick flick = Flicks.ProcessMessage(lParam, wParam);
            if (flick != null)
            {
                if (flick.Data.Direction == FLICKDIRECTION.FLICKDIRECTION_LEFT)
                    Scroller("left"); //scrolls left
                else if (flick.Data.Direction == FLICKDIRECTION.FLICKDIRECTION_RIGHT)
                    Scroller("right"); //scrolls right
                else if (flick.Data.Direction == FLICKDIRECTION.FLICKDIRECTION_UP)
                    Scroller("up"); //move up
                else if (flick.Data.Direction == FLICKDIRECTION.FLICKDIRECTION_DOWN)
                    Scroller("down"); //move down
                    handled = true;
            }
        }
        return IntPtr.Zero;
    }

Thoughts/Suggestions? I’m pretty new to WPF.
Thanks

Answer 1

I solved this by capturing the mouse events and flick events in the ButtonsView so that they wouldn’t tunnel down to the GroupView.