/*
  * Refreshes all fields displayed in the window according to
  * current system objects states.
  */
 private void refreshDisplay()
 {
     clearDisplay();
     lstCustomers.ItemsSource = mFacade.GetAllCustomerNbs();
     if (mFacade.IsACustomerLoaded())
     {
         lblCustNumberValue.Content = mFacade.GetCurrentCustNb();
         txtCustName.Text           = mFacade.GetCurrentCustName();
         txtCustAddress.Text        = mFacade.GetCurrentCustAdress();
     }
 }
        // METHODS RELATED TO CURRENT CUSTOMER:

        /*
         * Refreshes the customer fields displayed in the window.
         */
        private void refreshCustomerDisplay()
        {
            if (mFacade.IsACustomerLoaded())
            {
                lblCustNumberValue.Content
                    = mFacade.GetCurrentCustNb().ToString();
                lblCustNameValue.Content
                    = mFacade.GetCurrentCustName();
                lblCustAddressValue.Content
                    = mFacade.GetCurrentCustAdress();
            }
        }
        /*
         * Fills the labels of the invoice concerning the booking
         * details.
         */
        private void printDetails()
        {
            lblBookingNb.Content
                += " " + mFacade.GetCurrentBookNb().ToString();

            lblCustomerNb.Content
                += " " + mFacade.GetCurrentCustNb().ToString();

            lblCustomerDetails.Content
                += " " + mFacade.GetCurrentCustName();

            lblAddress.Content
                = mFacade.GetCurrentCustAdress();
        }