CODEWITHSUNDEEP
c#windows-phone-8windows-phonefile-storage
Dominic St-Pierre
Dominic St-Pierre

Reputation: 2459

Windows Phone 8 file are not persisted across app restart

I'm writing my first Windows Phone 8 app, and I'm just trying something simple. Read / Write file. Here's my two methods:

public static async Task<Week> Load()
{
    StorageFolder folder = ApplicationData.Current.LocalFolder;
    try
    {
        StorageFile mealsFile = await folder.GetFileAsync("file.txt");

        if (mealsFile != null)
        {
            using (var stream = await mealsFile.OpenAsync(FileAccessMode.Read))
            {
                var serializer = new DataContractSerializer(typeof(List<MyTypeHere>));
                var w = (List<MyTypeHere>)serializer.ReadObject(stream.AsStreamForRead());
                if (w != null)
                    MyWeek.WeekList = new ObservableCollection<MyTypeHere>(w);
            }
        }
    }
    catch(FileNotFoundException fEx)
    {
        MyWeek = new Week();
    }

    return MyWeek;
}

public static async Task<bool> Save()
{
    try
    {
        StorageFolder folder = ApplicationData.Current.LocalFolder;
        StorageFile mealsFile = await folder.CreateFileAsync("file.txt", CreationCollisionOption.ReplaceExisting);
        using (var stream = await mealsFile.OpenAsync(FileAccessMode.ReadWrite))
        {
            using (var sw = stream.GetOutputStreamAt(0))
            {
                var serializer = new DataContractSerializer(typeof(List<MyTypeHere>));
                serializer.WriteObject(sw.AsStreamForWrite(), MyWeek.WeekList.ToList());

                await sw.FlushAsync();
            }
        }

        MyWeek = null;

        return true;
    }
    catch(Exception ex)
    {
        return false;
    }
}

I'm calling the Save (with breakpoint it works fiine), then call Load (with breakpoint) which load the file, the file exists and it populate my object graph.

When I close the app and restart it, the catch of the FileNotFoundException is caught. Why?

From what I can see the Local Folder is supposed to be persisting the file. What I'm missing that obviously should be obvious...

Thanks

Edit:

I'm using the Windows Phone emulator, and when I close it and hit F5 on Visual Studio, the file is not there anymore.

Upvotes: 0

Views: 95

Answers (1)

Dominic St-Pierre
Dominic St-Pierre

Reputation: 2459

Apparently by closing the emulator, the files in Local Storage are lost, thanks to @cdndevs via Twitter. I was closing the emulator each time I was stopping debugging instead of letting the emulator simply "stay" there between restart.

By stopping debugging and restarting the app without closing the emulator, the files are there. Well, not super intuitive I must admit, or it might just be me. Hope that help other people like me ;).

Upvotes: 1

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