正则表达式 – 需要正则表达式来验证用户名

foundMatch = Regex.IsMatch(subjectString,@"^(?=.*[a-z])w{7,15}s*$",RegexOptions.IgnoreCase);

也允许使用_,因为您在尝试时允许这样做.

所以基本上我使用三个规则.一个检查是否至少存在一个字母.
另一个检查字符串是否只包含alphas和_,最后我接受尾随空格,至少7个最多15个alpha.你的情况很好.坚持下去,你也会在这里回答问题:)

分解：

"
^           # Assert position at the beginning of the string
(?=         # Assert that the regex below can be matched,starting at this position (positive lookahead)
   .        # Match any single character that is not a line break character
      *     # Between zero and unlimited times,as many times as possible,giving back as needed (greedy)
   [a-z]    # Match a single character in the range between “a” and “z”
)
w          # Match a single character that is a “word character” (letters,digits,etc.)
   {7,15}   # Between 7 and 15 times,giving back as needed (greedy)
s          # Match a single character that is a “whitespace character” (spaces,tabs,line breaks,etc.)
   *        # Between zero and unlimited times,giving back as needed (greedy)
$          # Assert position at the end of the string (or before the line break at the end of the string,if any)
"