回答

using System;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;

namespace HelloWorldApplication
{
    class HelloWorld
    {
        static void Main(string[] args) {
            System.Net.WebClient client = new WebClient();
            byte[] page = client.DownloadData("http://www.bfw.wiki");
            string content = System.Text.Encoding.UTF8.GetString(page);
            string regex = "href=[\\\"\\\'](http:\\/\\/|\\.\\/|\\/)?\\w+(\\.\\w+)*(\\/\\w+(\\.\\w+)?)*(\\/|\\?\\w*=\\w*(&\\w*=\\w*)*)?[\\\"\\\']";
            Regex re = new Regex(regex);
            MatchCollection matches = re.Matches(content);

            System.Collections.IEnumerator enu = matches.GetEnumerator();
            while (enu.MoveNext() && enu.Current != null) {
                Match match = (Match)(enu.Current);
                Console.Write(match.Value + "\r\n");
            }
        }
    }
}