How to figure out when control is visible to user?

Question

I would like to know how to figure out when a control is visbile to user and when not?

Let says I am writing a custom control which extends a TextBox and I would like to know when is visible to do some custom logic inside the handler triggered on visible changed.

How to do so? How to figure out if the control is visible to user or not? The custom control which extends a TextBox could be inside a Button for instance and Button could receive Visibility.Collapsed so all its inner nested controls would be invisibe and thats what I want to know. How to figure out if visible no matter what value to Visibility property is set?

score 10 · Accepted Answer · edited May 23 '17 at 12:31

10

You should use UIElement.IsVisibleChanged event. It occurs when value of the IsVisible changes that is read-only dependency property and indicates elements Visibility on UI.
UIElement.LayoutUpdated - event that could be used for recalculating controls visibility.

UPDATE. Seems like it is exact duplicate:
In WPF, how can I determine whether a control is visible to the user?

edited May 23 '17 at 12:31

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answered Feb 25 '13 at 11:23

Anatolii Gabuza

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I edited my question. I am not talking about Visibility property. I am talking about visibility in general. Btw your link to IsVisibleChanged is not working – snowy hedgehog Feb 25 '13 at 11:25
@hedgehog Ok. Now I see what you meen. Updated. – Anatolii Gabuza Feb 25 '13 at 11:39
that is just a method that I have to call explicitly to figure out if visible. I would like to get notified by WPF if is visible or not. – snowy hedgehog Feb 25 '13 at 11:43
@hedgehog You could use this method in `LayoutUpdated` on parent `Window`. – Anatolii Gabuza Feb 25 '13 at 12:47
What do you mean exactly with using this method in Layoutupdated on parent Window? – snowy hedgehog Feb 25 '13 at 14:32
The LayoutUpdated event seems to be triggered constantly. Why is that so? – snowy hedgehog Feb 26 '13 at 16:49
@hedgehog http://stackoverflow.com/questions/1577240/wpf-layoutupdated-event-firing-repeatedly take a look. – Anatolii Gabuza Feb 26 '13 at 22:34
A control can be rendered (IsVisible == true) but can still be hidden by other controls hiding it. In such case it not visible to the user. Here is a different solution I wrote in a similar thread: http://stackoverflow.com/questions/1517743/in-wpf-how-can-i-determine-whether-a-control-is-visible-to-the-user/42254899#42254899 – Ofer Barasofsky Feb 21 '17 at 15:47

How to figure out when control is visible to user?

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