System.IO.IsolatedStorage.IsolatedStorageFile.CreateDirectory C# (CSharp) Method

        public void CreateDirectory(string dir) { }
        public System.IO.IsolatedStorage.IsolatedStorageFileStream CreateFile(string path) { throw null; }

        protected BaseStorageCache(IsolatedStorageFile isf, string cacheDirectory, ICacheFileNameGenerator cacheFileNameGenerator, long cacheMaxLifetimeInMillis = DefaultCacheMaxLifetimeInMillis)
        {
            if (isf == null)
            {
                throw new ArgumentNullException("isf");
            }

            if (String.IsNullOrEmpty(cacheDirectory))
            {
                throw new ArgumentException("cacheDirectory name could not be null or empty");
            }

            if (!cacheDirectory.StartsWith("\\"))
            {
                throw new ArgumentException("cacheDirectory name should starts with double slashes: \\");
            }

            if (cacheFileNameGenerator == null)
            {
                throw new ArgumentNullException("cacheFileNameGenerator");
            }

            ISF = isf;
            CacheDirectory = cacheDirectory;
            CacheFileNameGenerator = cacheFileNameGenerator;
            CacheMaxLifetimeInMillis = cacheMaxLifetimeInMillis;

            // Creating cache directory if it not exists
            ISF.CreateDirectory(CacheDirectory);
        }