簡(jiǎn)單實(shí)例：

    string s = "2005-2-21";
    regex reg = new regex(@"(?<y>/d{4})-(?<m>/d{1,2})-(?<d>/d{1,2})",regexoptions.compiled);
         
    match match = reg.match(s);
    int year =  int.parse(match.groups["y"].value);
    int month = int.parse(match.groups["m"].value);
    int day = int .parse(match.groups["d"].value);
    datetime time = new datetime(year,month,day);