Partially completed text boxes and tombstoning in Windows Phone 7

Question

When I use TwoWay data binding to a view model on a page, then from what I have observed, the view model is only updated when the focus leaves the field (eg. a TextBox). This behaviour matches the description in Updating the Data Source.

If the application is tombstoned, then most examples I've seen just persist the view model in the page state, and reload them if it is activated again.

From what I can see, this means that if the user hadn't caused focus to be lost from the text box they were editing, the current value isn't copied to the view model, and so it isn't saved.

Is that what a user (and also Microsoft's Application Certification process) would expect from a WP7 application?

Answer 1

Saving partially entered text across tombstoning isn't a requirement for marketplace acceptance testing.

However, you should persist the data if it makes sense in the context of the application and that is what would give the best user experience.

DO NOT base your application experience on the way the framework synchronises data to a view model. Do what's best for the user.

If it made sense for the application to save this information, as a user, I would want it to and I woudn't care for whatever technical reason you gave for not doing this.