How do I programmatically read the value of an attached dependency property?

Question

So I have a Button with an AutomationId (used by Microsoft UI Automation) like so:

<Button Name="myButton" AutomationId="myButtonAutomationID" 

Programmatically, I have the button (myButton) in code, how do I get the value of the 'AutomationId' property attached to that button?

Answer 1

DependencyObject.GetValue should do the job:

string automationId = 
    (string)myButton.GetValue(AutomationProperties.AutomationIdProperty);

Answer 2

Fundamentally, just as you would with any other DependencyProperty ; the ordinary properties on your object serve (or should serve) as simple wrappers around DependencyObject.GetValue and .SetValue , so all you need to do is call GetValue yourself and pass in your static readonly instance of your attached DependencyProperty :

var value = myButton.GetValue(yourDependencyProperty);

Answer 3

var automationId = AutomationProperties.GetAutomationId(myButton);

As is standard for dependency properties, this wrapper method will do the job of calling DependencyObject.GetValue for you, and casting the value to the correct type.