如何在C＃正则表达式中获取捕获的组的名称？

有没有办法在C＃中获取捕获的组的名称？

string line = "No.123456789  04/09/2009  999";
Regex regex = new Regex(@"(?<number>[\d]{9})  (?<date>[\d]{2}/[\d]{2}/[\d]{4})  (?<code>.*)");

GroupCollection groups = regex.Match(line).Groups;

foreach (Group group in groups)
{
    Console.WriteLine("Group: {0}, Value: {1}", ???, group.Value);
}

我想得到这个结果：

组：[我不知道该怎么办]，值：123456789 04/09/2009 999
组：数字，值：123456789
组：日期，值：04/09/2009
组：代码，值：999

使用GetGroupNames可以获取表达式中的组列表，然后使用这些名称作为groups集合中的键对它们进行迭代。

例如，

GroupCollection groups = regex.Match(line).Groups;

foreach (string groupName in regex.GetGroupNames())
{
    Console.WriteLine(
       "Group: {0}, Value: {1}",
       groupName,
       groups[groupName].Value);
}

最干净的方法是使用以下扩展方法：

public static class MyExtensionMethods
{
    public static Dictionary<string, string> MatchNamedCaptures(this Regex regex, string input)
    {
        var namedCaptureDictionary = new Dictionary<string, string>();
        GroupCollection groups = regex.Match(input).Groups;
        string [] groupNames = regex.GetGroupNames();
        foreach (string groupName in groupNames)
            if (groups[groupName].Captures.Count > 0)
                namedCaptureDictionary.Add(groupName,groups[groupName].Value);
        return namedCaptureDictionary;
    }
}

扩展方法到位后，您可以获取如下名称和值：

    var regex = new Regex(@"(?<year>[\d]+)\|(?<month>[\d]+)\|(?<day>[\d]+)");
    var namedCaptures = regex.MatchNamedCaptures(wikiDate);

    string s = "";
    foreach (var item in namedCaptures)
    {
        s += item.Key + ": " + item.Value + "\r\n";
    }

    s += namedCaptures["year"];
    s += namedCaptures["month"];
    s += namedCaptures["day"];

从.NET 4.7开始，有可用的Group.Name属性。

您应该使用GetGroupNames();并且代码将如下所示：

    string line = "No.123456789  04/09/2009  999";
    Regex regex = 
        new Regex(@"(?<number>[\d]{9})  (?<date>[\d]{2}/[\d]{2}/[\d]{4})  (?<code>.*)");

    GroupCollection groups = regex.Match(line).Groups;

    var grpNames = regex.GetGroupNames();

    foreach (var grpName in grpNames)
    {
        Console.WriteLine("Group: {0}, Value: {1}", grpName, groups[grpName].Value);
    }

正则表达式类是实现这一目标的关键！

foreach(Group group in match.Groups)
{
    Console.WriteLine("Group: {0}, Value: {1}", regex.GroupNameFromNumber(group.Index), group.Value);
}

http://msdn.microsoft.com/zh-CN/library/system.text.regularexpressions.regex.groupnamefromnumber.aspx