/// <remarks>
        /// Displays customer details and contacts if any customer is selected in table
        /// </remarks>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void listCustomers_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (listCustomers.SelectedItem != null)
            {
                CustomerBO selectedCustomer = (CustomerBO)listCustomers.SelectedItem;
                lblCompanyName.Content = selectedCustomer.CompanyName;
                lblContactPerson.Content = selectedCustomer.ContactPerson;

                ContactService contactSrv = new ContactService();
                List<ContactBO> customerContacts = contactSrv.getAllFromTableByCustomerID(selectedCustomer.CustomerID);

                ContactTypeService contactTypeSrv = new ContactTypeService();

                //adding ContactType Name to ContactBO Obj. by ContactType ID
                foreach (ContactBO customerContact in customerContacts)
                {
                    customerContact.ContactTypeName = contactTypeSrv.getNameById(customerContact.ContactTypeID);
                }

                listContacts.ItemsSource = customerContacts;
            }
        }
        /// <remarks>
        /// Fills the Booking detailed view on bottom of the page with the _selectedBooking info.
        /// </remarks>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void UnconfBookingsGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {

            CultureInfo culture = new CultureInfo("de-DE");
            _selectedBooking = (BookingBO)UnconfBookingsGrid.SelectedItem;

            // if there is a booking with active selection in the DataGrid, textBlocks are filled with booking info
            if (_selectedBooking != null)
            {
                txtID.Text = _selectedBooking.BookingID.ToString();
                txtDate.Text = _selectedBooking.Date.ToString("d", culture);
                txtRoom.Text = _selectedBooking.Room;
                txtParticipants.Text = _selectedBooking.Participants.ToString();
                txtCustomer.Text = _selectedBooking.CustomerCompany;
                txtCustomerPIC.Text = _selectedBooking.CustomerContactPerson;
                txtCreated.Text = _selectedBooking.Created.ToString("d", culture);
                txtAdmin.Text = _selectedBooking.Admin;
                txtAdditional.Text = _selectedBooking.AdditionalInfo;

                //in ideal world must never execute first condition
                if (_selectedBooking.Confirmed != null)
                {
                    txtConfirmed.Text = ((DateTime)_selectedBooking.Confirmed).ToString("g", culture);
                }
                else txtConfirmed.Text = "";// must always execute this condition, as this is Unconfirmed Booking View

                // displays first available contact value, if there is any in the table
                ContactService contactSrv = new ContactService();
                List<ContactBO> contacts = contactSrv.getAllFromTableByCustomerID(_selectedBooking.CustomerID);
                if (contacts.Count > 0)
                {
                    txtContact.Text = contacts[0].Value.ToString();
                }
                else txtContact.Text = "";
        
            }
        }
        /// <remarks>
        /// updates Customer Contact list after adding/updating contacts.
        /// </remarks>
        private void updateListContacts()
        {
            ContactTypeService contactTypeSrv = new ContactTypeService();
            ContactService contactSrv = new ContactService();
            List<ContactBO> customerContacts = contactSrv.getAllFromTableByCustomerID(_selectedCustomer.CustomerID);

            //adding ContactType Name to ContactBO Obj. by ContactType ID
            foreach (ContactBO customerContact in customerContacts)
            {
                customerContact.ContactTypeName = contactTypeSrv.getNameById(customerContact.ContactTypeID);
            }

            listContacts.ItemsSource = customerContacts;
        }