IsolatedStorageSettings needs Update?

Question

I'm using IsolatedStorageSettings on WP7 to store an objects list:

List<T>

I need to search an item inside my list and to update some properties of the searched item.

I'm using this code:

List<Article> listArt = null;
IsolatedStorageSettings.ApplicationSettings.TryGetValue("ArticleListStorage", out listArt);

var queryList = (from anItem in listArt where (anItem.Id == _id) select anItem).ToList<Article>();

a = queryList[0] as Article;

//mark Article as read
a.Readed = true;

When I continuously navigate the various page inside the app, I can see the property Readed correctly evalued.

But, when I click on WP7 Start button and reopen my app (without close emulator) I see the property not correctly evalued.

Need I to update my object inside list and so inside Isolated Storage?

Not updated by reference?

I tried also this, ant it doesn't work:

listArt[0].Readed = true;
listArt[0].Favorite = true;

IsolatedStorageSettings.ApplicationSettings["ArticleListStorage"] = listArt;

IsolatedStorageSettings.ApplicationSettings.Save();

What is wrong?

Thank you so much!

Matt Lacey Matt Lacey · Accepted Answer · 2010-11-29T16:36:54

You can either explicitly call Save() on the settings or wait for the app to close normally and then they will be saved automatically.

As a general rule I'd suggest always explicitly saving settings once you change them. (Unless you have a very good reason not to.)

What's happening in your situation is that you are pressing the start button which causes your app to tombstone. When you launch a new instance of the app the tombstoned version is destroyed without all the code which normally runs on application close (including auto-saving settings) being executed.

Here's and example of using Save:

var settings = IsolatedStorageSettings.ApplicationSettings;

if (settings.Contains("some-key"))
{
    settings.Remove("some-key");
}

settings.Add("some-key", "my-new-value");
settings.Save();

IsolatedStorageSettings needs Update?

2 Answers