public override void DeleteAll(string uniqueName)
        {
            lock (_cache) {
                if (_cache.ContainsKey(uniqueName))
                {
                    _cache.Remove(uniqueName);
                }
            }

            // find the directory.
            //
            var dir = FileItem.DirectoryHash(uniqueName);

            if (IsoStore.DirectoryExists(dir))
            {
                PriorityQueue.AddStorageWorkItem(() =>
                {
                    lock (LockObject) {
                        var files = IsoStore.GetFileNames(dir + "\\*");
                        foreach (var f in files)
                        {
                            var path = Path.Combine(dir, f);
                            DeleteFileHelper(IsoStore, path);
                        }
                    }
                });
            }
        }
        public override IEnumerable <CacheItemInfo> GetItems(string uniqueName)
        {
            CacheItemInfo item;

            if (_cache.TryGetValue(uniqueName, out item))
            {
                return(new CacheItemInfo[] { item });
            }

            // find the directory.
            //
            var dir = FileItem.DirectoryHash(uniqueName);


            if (IsoStore.DirectoryExists(dir))
            {
                lock (LockObject) {
                    string[] files = null;

                    try
                    {
                        files = IsoStore.GetFileNames(dir + "\\*");
                    }
                    catch (IsolatedStorageException)
                    {
                        // intermittent IsoStore exceptions on shutdown.
                        files = new string[0];
                    }

                    List <CacheItemInfo> items = new List <CacheItemInfo>();

                    foreach (var f in files)
                    {
                        CacheItemInfo cii = FileItem.FromFileName(f);

                        if (cii != null)
                        {
                            items.Add(cii);
                        }
                    }

                    var orderedItems = from i in items
                                       where i.UniqueName == uniqueName
                                       orderby i.ExpirationTime descending
                                       select i;

                    foreach (var i in orderedItems)
                    {
                        if (item == null)
                        {
                            item = i;
                            continue;
                        }

                        Delete(i);
                    }

                    if (item != null)
                    {
                        _cache[uniqueName] = item;
                        return(new CacheItemInfo[] { item });
                    }
                }
            }
            return(new CacheItemInfo[0]);
        }