Identify and find element in XAML tree by XPath

Question

Is there any possibility to use XPath in order to identify each XAML element in running application?

For example if I have following XAML structure.

<Page>
    <StackPanel>
        <Button />
        <Button />
    </StackPanel>
</Page>

I would like to know XPath of the second button for instance and when I have it, I would like to retrieve the button thanks to XPath afterwards.

I know that I can work with XPath without any problems if I have XmlDocument but I would like to achieve the same stuff with elements from running application if it is possible.

Can you show code that you'd like to write? Not very clear what "the same stuff with elements from running application" means... — Alexei Levenkov, Dec 06 '16 at 16:32
Sounds like a pretty painful way to go. If you are going to want to access controls from the code-behind it makes sense to name them (x:Name="someName") and then access them based on their name ( Button btn = (Button)this.FindName("someName"); ) — Asnivor, Dec 06 '16 at 16:37
@AlexeiLevenkov I mean when I click on the second button I would like to get "/Page/StackPanel/Button[index]". Afterwards thanks to XPath expression I would like to find the button. — Jakub Krampl, Dec 06 '16 at 16:41
@Asnivor Probably painful, however, I am curious whether it is possible or not (without naming). — Jakub Krampl, Dec 06 '16 at 16:42
You can... but I don't believe there is an existing implementation. If you really want to make one - read on XPathNavigator which was designed to allow XPath navigation over arbitrary trees... But this approach never took off to my knowledge - so hard to find any useful samples/implementations. — Alexei Levenkov, Dec 06 '16 at 17:23
@AlexeiLevenkov Thank you for your feedback. If you put this as an answer, I will accept it. — Jakub Krampl, Dec 14 '16 at 11:18

score 1 · Answer 1 · edited May 23 '17 at 10:30

There is actually no such XAML structure to apply an XPath on at runtime. The XAML parser will parse your XAML markup and create a tree of elements that make up the user interface that you see on the screen.

So if you need to find the second button in a StackPanel once it has been constructed at runtime you should either look directly in the StackPanel's Children collection:

Button secondButton = sp.Children[1] as Button;

...or use the VisualTreeHelper class to find it in the visual tree: Find control in the visual tree

Identify and find element in XAML tree by XPath

1 Answers1