/// <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>
        /// 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;
        }