/// <summary>
        /// Opens an existing file.
        /// </summary>
        public void Open(LiteDatabase db, string location)
        {
            var newItem = new DatabaseModel(this, db, location);

            OpenedDatabases.Add(newItem);
            SelectedDatabase = newItem;
        }
        /// <summary>
        /// Closes the currently selected database.
        /// </summary>
        public void CloseDatabase()
        {
            if (SelectedDatabase == null)
            {
                throw new ArgumentNullException(nameof(SelectedDatabase));
            }

            using (SelectedDatabase)
            {
                OpenedDatabases.Remove(SelectedDatabase);
            }

            SelectedDatabase = null;
        }