public static List <Item> GetCollection()
        {
            if (File.Exists(collectionFilename))
            {
                try
                {
                    return(ObjectSerializer <List <Item> > .DeserializeBinaryObject(collectionFilename));
                }
                catch (Exception err)
                {
                    throw;
                }
                return(new List <Item>());
            }

            else
            {
                return(new List <Item>());
            }
        }