Default WPF HitTest behaviour with Hidden/Collapsed elements

Question

in WPF when using VisualTreeHelper.HitTest even hidden Elements are found. To skip this elements and only return a result for visible ones, i created a HitTestFilter like the following :

///This Filter should cut all invisible or not HitTest Enabled Elements
private static HitTestFilterBehavior MyHitTestFilter(DependencyObject target)
{
    var uiElement = target as UIElement;
    if (uiElement != null){
        if(!uiElement.IsHitTestVisible || !uiElement.IsVisible))
            return HitTestFilterBehavior.ContinueSkipSelfAndChildren;
    }
    return HitTestFilterBehavior.Continue;
}

This Filter does his job, but i like to know what the default WPF HitTesting does in this case? Does it use a similar filter? Are there any other, maybe better options for doing this?

To clarify a short description :

In the image there is

1. A Layout Container as the root element
2. Button1 which is visible
3. Above Button1 is Button2 which is invisible

If i got such a layout and do a mouseclick in the green area of Button2, WPF skips Button2 and the click event appears on Button1.

If i do manual HitTesting without the filter described earlier, i will get Button2 as the result.

So the question is, what is the default behaviour/filter WPF is using?

Thanks in advance for any suggestions.

Paske

Can't reproduce this for Collapsed elements. And that would be strange anyway as they would not have been laid out. – Lyn

oh you are right. i will edit my question, i thought i tested it with collapsed. sorry. – Paske

There is a lot to explain about this. You might however get a .Net decompiler (like the free JetBrains dotPeek) and take a look at the implementation of e.g. the UIElement.InputHitTest method. – Lyn

Possible duplicate of WPF UIElement.IsHitTestVisible=false; still returning hits? – Quotidian

Answer 1

I know this is rather old question, but I had similar issue recently and got it working by using UIElement.InputHitTest method.

I replaced

HitTestResult hitTest = VisualTreeHelper.HitTest(rootVisual, point);
IInputElement source = hitTest?.VisualHit as IInputElement;

With

IInputElement source = rootVisual.InputHitTest(point);

The second version skips invisible elements (while the first doesn't).

Teador