/// <remarks>
        /// Adds new contact  entry with data provided by customer.
        /// Validates presence of user input before saving.
        /// </remarks>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnAddContact_Click(object sender, RoutedEventArgs e)
        {
            txtError.Content = "";
            ContactTypeBO cboxContact = (ContactTypeBO)cboxContacts.SelectedItem;
            

            if (null == cboxContact)
            {
                txtError.Content = "palun valige liik.";
                return;
            }
            
            int sellectedContactTypeID = cboxContact.ContactTypeID;


            int thisCustomerID = _selectedCustomer.CustomerID;
            string valueToAdd = txtContactTypeValue.Text;

            if (!String.IsNullOrEmpty(valueToAdd))
            {
                ContactService contactSrv = new ContactService();
                contactSrv.addNew(thisCustomerID, sellectedContactTypeID, valueToAdd, DateTime.Now);

                updateListContacts();
                txtContactTypeValue.Text = "";
            }
            else
            {
                txtError.Content = "Väärtus on tühi!";
            }
        }
        private static void fullFillContactTable()
        {
            ContactTypeService contactTypeSrv = new ContactTypeService();
            List<ContactTypeBO> contactTypes = contactTypeSrv.getAllFromTable();
            Assert.AreNotEqual(0, contactTypes.Count(), string.Format("There should be values in 'ContactType' Table."));
            int existingContactTypeID = contactTypes.ElementAt(0).ContactTypeID;
            
            CustomerService customerSrv = new CustomerService();
            List<CustomerBO> customers = customerSrv.getAllFromTable();
            Assert.AreNotEqual(0, customers.Count(), string.Format("There should be values in 'Customer' Table."));
            int existingCustomerID = customers.ElementAt(0).CustomerID;

            //TODO: Verify that contact cannot be created before Customer (CustomerID foreign key)
            //TODO: Verify that contact cannot be created before ContactType (ContactTypeID foreign key)
            ContactService contactSrv = new ContactService();
            contactSrv.addNew(existingCustomerID, existingContactTypeID, "val_skype", DateTime.Now);//TODO: take first from list
            contactSrv.addNew(existingCustomerID, existingContactTypeID, "val_mail", DateTime.Now);
            contactSrv.addNew(existingCustomerID, existingContactTypeID, "val_phone", DateTime.Now);
            List<ContactBO> contacts = contactSrv.getAllFromTable();
            Assert.AreNotEqual(0, contacts.Count(), string.Format("There should be values in 'Contact' Table."));
        }