private void saveNewCustomer_Click(object sender, RoutedEventArgs e)
        {
            //CustomerManagement parentWindow = (CustomerManagement)Owner;

            Customer newCustomer = new Customer();

            newCustomer.Id = CustomerRepository.Count() + 1;
            newCustomer.EntryDate = DateTime.Now;
            newCustomer.FirstName = firstNameBox.Text;
            newCustomer.LastName = lastNameBox.Text;
            newCustomer.TelephoneNumber = telephoneNumberBox.Text;
            newCustomer.Email = emailBox.Text;
            newCustomer.Notes = notesBox.Text;


            CustomerRepository.Add(newCustomer);
        }
 // Event of selection (when grid item clicked it is selected)
 private void dataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
 {
     // row (selected item) within the data grid (dataGrid) cast within 
     // the customer class (adds functionality)
     SelectedLogEntry = (Customer)dataGrid.SelectedItem;
 }