如何从.NET RegEx中提取子字符串？

Question

我有一个包含一个(或多个)键/值对的XML文件.对于这些对中的每一对,我想提取一个两字节十六进制值的值.

所以XML包含这个片段:

<key>LibID</key><val>A67A</val>

我可以使用以下表达式匹配,括号中的ID.

Match match = Regex.Match(content, @"<key>LibID</key><val>([a-fA-F0-9]{4})</val>");

if (match.Success)
{
  Console.WriteLine("Found Match for {0}\n", match.Value);
  Console.WriteLine("ID was {0}\n", "Help me SO!");
}

如何更改最后一部分,以便从匹配中返回ID？

干杯!

Answer 1

我想你想要的

match.Groups[1].Value

(正如Dillie-O在评论中指出的那样,它是第1组,因为第0组始终是整场比赛.)

简短但完整的测试程序:

using System;
using System.Text.RegularExpressions;

class Program
{
  static void Main()
  {
    Regex regex = new Regex("<key>LibID</key><val>([a-fA-F0-9]{4})</val>");
    Match match = regex.Match("Before<key>LibID</key><val>A67A</val>After");

    if (match.Success)
    {
      Console.WriteLine("Found Match for {0}", match.Value);
      Console.WriteLine("ID was {0}", match.Groups[1].Value);
    }      
  }
}

输出:

Found Match for <key>LibID</key><val>A67A</val>
ID was A67A