c# - 排除字符串开头和结尾的特殊字符

Question

我想要一个正则表达式来排除字符串开头和结尾的特殊字符

我试过这段代码，但它不起作用

String strFileName = Regex.Replace(FileName, @"[^A-Za-z0-9-_ ]", "");

<asp:RegularExpressionValidator ID = "Regular" 
            ValidationGroup = "valGroup" runat="server" ControlToValidate = "txtreport"
            ErrorMessage = "Please enter valid data."
            ValidationExpression = "([a-z]|[A-Z]|[0-9])*">
</asp:RegularExpressionValidator>

Answer 1

您几乎就在那里，只需添加 anchor 以将匹配项绑定(bind)到字符串的开头或结尾，并告诉正则表达式引擎匹配多个字符:

String strFileName = Regex.Replace(FileName, 
    @"^              # Match the start of the string
    [^A-Z0-9_ -]+    # followed by one or more characters except these
    |                # or
    [^A-Z0-9_ -]+    # Match one or more characters except these
    $                # followed by the end of the string", 
    "", RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);

此外，您的 ValidationExpression很奇怪。

ValidationExpression="[a-zA-Z0-9]*"

意思相同，但不允许 _ , <space>和 -您的“特殊字符替换器”忽略了它。所以你可能想使用

ValidationExpression="[a-zA-Z0-9_ -]*"