IsolatedStorage not saving List<MyObject> after app restart WP7 - list

Question

I'm developing an application where I need to save a List of objects of type ExerciseObject. I don't understand why this data isn't persisting in the IsolatedStorageSettings after application restart while all of my other data is (including other objects I created).
Here is the ExerciseObject class in which I create a list containing this object type to be stored to IsolatedStorageSettings. The interesting part is that while the application is open, the data is saved, it's just once I restart the app that only the List of ExerciseObject data is lost.
public class ExerciseObject
{
public ExerciseObject(string description, int caloriesBurned, bool burned)
{
this.Description = description;
this.CaloriesBurned = caloriesBurned;
this.Burned = burned; // true if activity, false if food
if (this.Burned) // text should be green
this.TextColor = new SolidColorBrush(Colors.Green);
else
this.TextColor = new SolidColorBrush(Colors.Red);
}
public string Description { get; set; }
public int CaloriesBurned { get; set; }
public bool Burned { get; set; }
public SolidColorBrush TextColor { get; set; }
}
This is how I am adding to the list:
ExerciseObject exerciseObj = new ExerciseObject(this.txtActivity.Text, int.Parse(this.txtBurned.Text), true);
List<ExerciseObject> tempList = (List<ExerciseObject>)IsolatedStorageSettings.ApplicationSettings["ListExerciseObjects"];
tempList.Add(exerciseObj);
IsolatedStorageSettings.ApplicationSettings["ListExerciseObjects"] = tempList;
And this is how I am accessing the List:
// Get the list of exercise objects from the isolated storage
List<ExerciseObject> exerciseObjects = (List<ExerciseObject>)IsolatedStorageSettings.ApplicationSettings["ListExerciseObjects"];
// Setting data context of listBox to the list of exercise objects for now
this.listBoxEntries.DataContext = exerciseObjects;

Answer 1

I tried your example, and it seems that the type SolidColorBrush is not serializable. The phone internals calls the iso storage "Save" method when the app exists and this is failing silently. to repro, remove the TextColor property or apply the "IgnoreDataMemberAttribute" on the property and observe that the issue goes away.
There are various ways to go about fixing this. I would personally derive the type of brush to apply at runtime, from your "burned" property.
I have attached a working example of your code which now stores the actual color as opposed to a SolidColorBrush object if you still wish to go store it.
Main.cs
// Constructor
public MainPage()
{
InitializeComponent();
BindExercises();
}
private void AddExercise(object sender, RoutedEventArgs e)
{
var exercise = new ExerciseObject("Activity added at: " + DateTime.Now.Ticks, (DateTime.Now.Second + 200), true);
IsolatedStorageSettingsManager.AddToCollection("ListExerciseObjects", exercise);
this.BindExercises();
}
private void BindExercises()
{
// Setting data context of listBox to the list of exercise objects for now
this.listBoxEntries.ItemsSource = IsolatedStorageSettingsManager.Get<IEnumerable<ExerciseObject>>("ListExerciseObjects").ToObservableCollection();
}
private void RemoveAllExercises(object sender, RoutedEventArgs e)
{
IsolatedStorageSettingsManager.Remove("ListExerciseObjects");
this.BindExercises();
}
public static class EnumerableExtensions
{
public static ObservableCollection<T> ToObservableCollection<T>(this IEnumerable<T> myList)
{
if (myList == null) return null;
var oc = new ObservableCollection<T>();
foreach (var item in myList)
oc.Add(item);
return oc;
}
}
public class ExerciseObject
{
public ExerciseObject() { }
public ExerciseObject(string description, int caloriesBurned, bool burned)
{
this.Description = description;
this.CaloriesBurned = caloriesBurned;
this.Burned = burned; // true if activity, false if food
if (this.Burned) // text should be green
this.Color = Colors.Green;
else
this.Color = Colors.Red;
}
public string Description { get; set; }
public int CaloriesBurned { get; set; }
public bool Burned { get; set; }
public Color Color { get; set; }
[IgnoreDataMemberAttribute]
public SolidColorBrush TextColor
{
get
{
return new SolidColorBrush(this.Color);
}
}
}
public class IsolatedStorageSettingsManager
{
private static readonly IsolatedStorageSettings isolatedStorageSettings = IsolatedStorageSettings.ApplicationSettings;
public static void Add<T>(string key, T value)
{
if (isolatedStorageSettings.Contains(key))
{
isolatedStorageSettings[key] = value;
}
else
{
isolatedStorageSettings.Add(key, value);
}
Save();
}
public static T Get<T>(string key, T #default = default(T))
{
T value;
if (isolatedStorageSettings.TryGetValue(key, out value))
{
return value;
}
return #default; // TODO: tell it what to do if the key is not found.
}
/// <summary>
/// Special [very crude] method which handles collections.
/// </summary>
/// <typeparam name="T">
/// The type of object to be serialized.
/// </typeparam>
/// <param name="key">
/// The key to assign to the object.
/// </param>
/// <param name="newValue">
/// The new record to add.
/// </param>
/// <returns>
/// The newly updated collection.
/// </returns>
public static IEnumerable<T> AddToCollection<T>(string key, T newValue) where T : class
{
List<T> currentValues;
if (isolatedStorageSettings.Contains(key))
{
currentValues = isolatedStorageSettings[key] as List<T>;
if (currentValues == null)
{
throw new InvalidCastException("The current values in the isolated storage settings " + key + "is not of a valid type");
}
currentValues.Add(newValue);
isolatedStorageSettings[key] = currentValues;
}
else
{
currentValues = new List<T> { newValue };
isolatedStorageSettings.Add(key, currentValues);
}
Save();
return currentValues;
}
public static void Remove(string key)
{
if (isolatedStorageSettings.Contains(key))
{
isolatedStorageSettings.Remove(key);
Save();
}
}
private static void Save()
{
isolatedStorageSettings.Save();
}
}
Xaml
<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Button Content="Add Exercise" Click="AddExercise" />
<Button Grid.Row="1" Content="Clear All" Click="RemoveAllExercises" />
<ListBox x:Name="listBoxEntries" Grid.Row="2">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Description }" />
<TextBlock Margin="15 0 0 0" Text="{Binding CaloriesBurned }" Foreground="{Binding TextColor}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>