void SetBillingCountry() { countryPicker.SelectedIndex = countryPicker.SelectedIndex > -1 ? countryPicker.SelectedIndex : 0; var selectedValue = countryPicker.Items[countryPicker.SelectedIndex]; _currentDiscoveredCountry = _countryDiscoverer.DiscoverCountry(selectedValue); postcodeEntry.Placeholder = _currentDiscoveredCountry.GetPostcodeTitle(); postcodeEntry.Text = string.Empty; if (_currentDiscoveredCountry.IsPostcodeNumeric()) { postcodeEntry.Keyboard = Keyboard.Numeric; postcodeEntry.Digits = "0123456789"; } else { postcodeEntry.Keyboard = Keyboard.Text; postcodeEntry.Digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; } postcodeEntry.MaxLength = _currentDiscoveredCountry.GetPostcodeLength(); postcodeEntry.IsEnabled = _currentDiscoveredCountry.IsPostcodeRequired(); Validate(postcodeEntry); }