Helper to manage Isolated Storage on Windows phone

ISHelper.cs

using System;
using System.IO;
using System.IO.IsolatedStorage;

namespace Tools
{
    public abstract class ISHelper
    {
        private const string directory = "Storage";

        /// <summary>
        /// Check if an item exists in storage
        /// </summary>
        /// <param name="key">key for data</param>
        /// <returns>true if it exists. false otherwise</returns>
        public static bool HasItem(string key)
        {
            using (var store = IsolatedStorageFile.GetUserStoreForApplication())
            {
                return store.FileExists(Path.Combine(directory, key));
            }
        }

        /// <summary>
        /// Get an item from the storage 
        /// </summary>
        /// <param name="key">key for data</param>
        /// <returns>Null if empty. Data as string otherwise</returns>
        public static string GetItem(string key)
        {
            try
            {
                using (var store = IsolatedStorageFile.GetUserStoreForApplication())
                {
                    string filePath = Path.Combine(directory, key);

                    if (store.FileExists(filePath))
                    {
                        using (StreamReader reader = new StreamReader(store.OpenFile(filePath, FileMode.Open, FileAccess.Read)))
                        {
                            return reader.ReadToEnd();
                        }
                    }
                    else
                        return null;
                }

            }
            catch
            {
                return null;
            }
        }

        /// <summary>
        /// Put data in storage
        /// </summary>
        /// <param name="key">key of data</param>
        /// <param name="value">value to put in storage as string</param>
        /// <returns>true if okay, false otherwise</returns>
        public static bool SetItem(string key, string value)
        {
            try
            {
                using (var store = IsolatedStorageFile.GetUserStoreForApplication())
                {
                    if (!store.DirectoryExists(directory))
                        store.CreateDirectory(directory);

                    string filePath = Path.Combine(directory, key);

                    if (store.FileExists(filePath))
                    {
                        store.DeleteFile(filePath);
                    }

                    using (var isoFileStream = new IsolatedStorageFileStream(filePath, FileMode.OpenOrCreate, store))
                    {
                        using (var isoFileWriter = new StreamWriter(isoFileStream))
                        {
                            isoFileWriter.WriteLine(value);
                        }
                    }
                    return true;
                }
            }
            catch
            {
                return false;
            }
        }
    }
}