public static class IsolatedStorageCacheManager<T>
{
    public static void Store(string filename, T obj)
    {
        IsolatedStorageFile appStore = IsolatedStorageFile.GetUserStoreForApplication();
 
        using (IsolatedStorageFileStream fileStream = appStore.OpenFile(filename, FileMode.Create))
        {
            DataContractSerializer serializer = new DataContractSerializer(typeof(T));
            serializer.WriteObject(fileStream, obj);
        }
    }
    public static T Retrieve(string filename)
    {
        T obj = default(T);
        IsolatedStorageFile appStore = IsolatedStorageFile.GetUserStoreForApplication();
        if (appStore.FileExists(filename))
        {
            using (IsolatedStorageFileStream fileStream = appStore.OpenFile(filename, FileMode.Open))
            {
                DataContractSerializer serializer = new DataContractSerializer(typeof(T));
                obj = (T)serializer.ReadObject(fileStream);
            }
        }
        return obj;
    }
}