private void SaveButton_Click(object sender, RoutedEventArgs e)
        {
            DialogResult = true;

            if (contractor.GetBusinessName() != BusinessNameTextBox.Text)
            {
                contractor.SetBusinessName(BusinessNameTextBox.Text);
            }
            if (contractor.getFirstName() != FirstNameTextBox.Text)
            {
                contractor.setFirstName(FirstNameTextBox.Text);
            }
            if (contractor.getSurname() != SurnameTextBox.Text)
            {
                contractor.setSurname(SurnameTextBox.Text);
            }
            if (contractor.getAddress() != AddressTextBox.Text)
            {
                contractor.setAddress(AddressTextBox.Text);
            }
            if (contractor.getPhone() != PhoneNumberTextBox.Text)
            {
                contractor.setPhone(PhoneNumberTextBox.Text);
            }
            if (contractor.getEmail() != EmailTextBox.Text)
            {
                contractor.setEmail(EmailTextBox.Text);
            }

            MessageBox.Show("Contractor details have been changed.");
            this.Close();
        }