Uninitialize camera when application is deactivated

CameraExplorer/AboutPage.xaml.cs

@@ -13,6 +13,7 @@ namespace MapExplorer
 {
     public partial class AboutPage : PhoneApplicationPage
     {
+        CameraExplorer.DataContext _dataContext = CameraExplorer.DataContext.Singleton;
 
         public AboutPage()
         {
@@ -20,5 +21,15 @@ namespace MapExplorer
 
             versionTextBox.Text = XDocument.Load("WMAppManifest.xml").Root.Element("App").Attribute("Version").Value;
         }
+
+        protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
+        {
+            if (_dataContext.Device == null)
+            {
+                NavigationService.GoBack();
+            }
+
+            base.OnNavigatedTo(e);
+        }
     }
 }

CameraExplorer/App.xaml.cs

@@ -17,6 +17,8 @@ namespace CameraExplorer
 {
     public partial class App : Application
     {
+        private CameraExplorer.DataContext _dataContext = CameraExplorer.DataContext.Singleton;
+
         /// <summary>
         /// Provides easy access to the root frame of the Phone Application.
         /// </summary>
@@ -75,6 +77,7 @@ namespace CameraExplorer
         // This code will not execute when the application is closing
         private void Application_Deactivated(object sender, DeactivatedEventArgs e)
         {
+            _dataContext.UnitializeCamera();
         }
 
         // Code to execute when the application is closing (eg, user hit Back)

CameraExplorer/MainPage.xaml.cs

@@ -34,6 +34,7 @@ namespace CameraExplorer
 
             ApplicationBarMenuItem menuItem = new ApplicationBarMenuItem();
             menuItem.Text = "about";
+            menuItem.IsEnabled = false;
             ApplicationBar.MenuItems.Add(menuItem);
             menuItem.Click += new EventHandler(aboutMenuItem_Click);
 
@@ -86,6 +87,11 @@ namespace CameraExplorer
             {
                 b.IsEnabled = enabled;
             }
+
+            foreach (ApplicationBarMenuItem m in ApplicationBar.MenuItems)
+            {
+                m.IsEnabled = enabled;
+            }
         }
 
         private void SetCameraButtonsEnabled(bool enabled)

CameraExplorer/PreviewPage.xaml.cs

@@ -20,9 +20,16 @@ namespace CameraExplorer
 
         protected override void OnNavigatedTo(NavigationEventArgs e)
         {
-            _bitmap.SetSource(_dataContext.ImageStream);
+            if (_dataContext.Device == null)
+            {
+                NavigationService.GoBack();
+            }
+            else
+            {
+                _bitmap.SetSource(_dataContext.ImageStream);
 
-            image.Source = _bitmap;
+                image.Source = _bitmap;
+            }
 
             base.OnNavigatedTo(e);
         }

CameraExplorer/Properties/WMAppManifest.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Deployment xmlns="http://schemas.microsoft.com/windowsphone/2012/deployment" AppPlatformVersion="8.0">
   <DefaultLanguage xmlns="" code="en-US" />
-  <App xmlns="" ProductID="{94f53777-5783-47b2-9bcb-ce46ccb0f219}" Title="Camera Explorer" RuntimeType="Silverlight" Version="0.0.0.4" Genre="apps.normal" Author="" Description="" Publisher="" PublisherID="{cc336b25-5e51-419a-8c64-3c4a7a4383f4}">
+  <App xmlns="" ProductID="{94f53777-5783-47b2-9bcb-ce46ccb0f219}" Title="Camera Explorer" RuntimeType="Silverlight" Version="0.0.0.5" Genre="apps.normal" Author="" Description="" Publisher="" PublisherID="{cc336b25-5e51-419a-8c64-3c4a7a4383f4}">
     <IconPath IsRelative="true" IsResource="false">Assets\ApplicationIcon.png</IconPath>
     <Capabilities>
       <Capability Name="ID_CAP_NETWORKING" />

CameraExplorer/SettingsPage.xaml.cs

@@ -27,6 +27,16 @@ namespace CameraExplorer
             DataContext = _dataContext;
         }
 
+        protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
+        {
+            if (_dataContext.Device == null)
+            {
+                NavigationService.GoBack();
+            }
+
+            base.OnNavigatedTo(e);
+        }
+
         private void resetButton_Click(object sender, EventArgs e)
         {
             SetScreenButtonsEnabled(false);