validateLastName method
String? validateLastName (String value)
Implementation
static String? validateLastName(String value) \{
if (value.isEmpty) \{
return 'Lastname must not be left blank.';
\}
ignore: unnecessary_raw_strings
const String pattern = r"(?=.*?[A-Za-z]).+";
final RegExp regex = RegExp(pattern);
if (!regex.hasMatch(value)) \{
return "Invalid Lastname";
\}
return null;
\}