How can I tell which TextBox had focus last?

Question

I have an MVVM application with various TextBox controls and a virtual keypad. (This application is to run on a touch screen system, with no keyboard). To change the value of a TextBox, the user has to touch the TextBox and then use the virtual keypad to enter a number. How can my VM know which TextBox to change when it gets the command from the keypad?

Answer 1

The ViewMoel is unconcerned with the View, and as such this should not be passed to the ViewMdel.

If I needed to track this, I would use the View's codebehind (I know, I know) or create a WPF behavior* that does this for me.

*using Attached DependencyProperties, is normally how I do this.

Answer 2

if you mean WPF use FocusManager.GetFocusedElement also look here