Question

A WP 7.1 project starts with a Page that host a Panorama control. At some point user click on a ListBox, and this navigates the application to a details page.

In case the debugger is attached, everything stays on the screen as it should. But If I test an application either in emulator, or on the phone without a debugger, approximately in 5-10 seconds after the details page navigation, an application gets deactivated.

No unhanded exception, not closing, but deactivated even is raised. I have placed a message boxes in each of “exit handlers” to know exactly what happens and found out that it is deactivation.

No user input takes place after navigation and before the deactivation.

What may be the reason for such “no interaction” deactivation?

I don’t call no “deactivate” requests from code.

Additional info:
Details page is bound to a sample view model that is obtained via MVVM Light ViewModel locator. View model locator gets it from ninject kernel that is a static public property of an App object(Yes, I have made IOC container publicly available via App property. I know it probably is a horrible practice, but I doubt the problem is linked to that). The page initializes just fine and displays all the data from a sample view model class. It almost seems like an app is deactivated due to inactivity, but there is no such thing in WP7 as far as I know.

UPDATE

A deactivation takes place exactly 10 seconds afer I call this line:

((PhoneApplicationFrame)(Application.Current.RootVisual)).Navigate(new Uri("/Views/BookDetailsView.xaml", UriKind.Relative));

from a view model of a main application view. The problem view is a details view, not the main one.

The constructor for BookDetailsView is empty (default):

public partial class BookDetailsView : UserControl
    {
        public BookDetailsView()
        {
            InitializeComponent();
        }
    }

The XAML for the view binds it’s datacontext to a property of a mvvm light view model locator:

DataContext="{Binding Source={StaticResource Locator}, Path=BookDetails}"

The Locator resource is decleared in App.xaml and points to ViewModelLocator.cs.

The property that provides datacontext for a problem view is:

public static IBookDetailsViewModel BookDetailsStatic
        {
            get;
            set;
        }

        /// <summary>
        /// Gets the Main property.
        /// </summary>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance",
            "CA1822:MarkMembersAsStatic",
            Justification = "This non-static member is needed for data binding purposes.")]
        public IBookDetailsViewModel BookDetails
        {
            get
            {
                return BookDetailsStatic;
            }
        }

The BookDetailsStatic is initialized from the IoC container call in the ViewModelLocator ctor:

BookDetailsStatic = App.Kernel.Get<IBookDetailsViewModel>();

In a any scenario the call to get an IBookDetailsViewModel returns an instance of a

public class SampleBookDetailsViewModel: IBookDetailsViewModel

which has an empty constructor and a bunch of properties.

SOLVED
My view, that I have been navigating to, was declared as a UserControl, and should have been as PhoneApplicationPage.

Answer 1

BookDetailsView was decleared as a UserControl.

Navigating to a UserControl deactivates an application in 10 seconds.

Changing the type of a view to PhoneApplicationPage solves the problem.