internal static void SaveAccessToken()
        {
            if (config.DropboxAccessToken != null)
            {
                // get the config of dropbox
                Dropbox.DropBoxConfiguration dropBoxConfig =
                CloudStorage.GetCloudConfigurationEasy(nSupportedCloudConfigurations.DropBox) as
                Dropbox.DropBoxConfiguration;

                CloudStorage storage = new CloudStorage();

                // open the connection to the storage
                storage.Open(dropBoxConfig, config.DropboxAccessToken);

                Stream tokenStream = storage.SerializeSecurityToken(config.DropboxAccessToken);

                string fileFullPath = Path.Combine(Environment.CurrentDirectory, Environment.UserName + "-Dropbox.tok");

                // Create a FileStream object to write a stream to a file
                using (FileStream fileStream = System.IO.File.Create(fileFullPath, (int)tokenStream.Length))
                {
                    // Fill the bytes[] array with the stream data
                    byte[] bytesInStream = new byte[tokenStream.Length];
                    tokenStream.Read(bytesInStream, 0, (int)bytesInStream.Length);

                    // Use FileStream object to write to the specified file
                    fileStream.Write(bytesInStream, 0, bytesInStream.Length);
                }

                // close the cloud storage connection
                if (storage.IsOpened)
                {
                    storage.Close();
                }
            }
        }