isAzNum static method
【除字母和数字外无其他字符(只有字母数字的字符串)】返回true 否则false
No characters except letters and numbers (only alphanumeric strings)
Returns true Otherwise false
Implementation
static bool isAzNum(String str) {
return RegExp(r"^[a-zA-Z0-9]+$").hasMatch(str);
}