/// <summary>
        /// Constructor with no parameters
        /// </summary>
        public MainForm()
        {
            InitializeComponent();
            tbsDbContext  = new TBSDbContext();
            tbsRepository = new TBSRepository(tbsDbContext);


            this.cbxInputFormat.SelectedIndex = 0;
            this.txtBxSalesDiscPercent.Text   = "0";
            this.txtBxSalesMemFees.Text       = "0";
            LoadBooks();
            books           = this.tbsRepository.GetBooks();
            bookQuantityMap = new Dictionary <Book, int>();
        }
 /// <summary>
 /// constructor
 /// </summary>
 public WelcomeScreen()
 {
     InitializeComponent();
     tbsDbContext  = new TBSDbContext();
     tbsRepository = new TBSRepository(tbsDbContext);
 }