using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.Text.RegularExpressions;
namespace ConsoleApplication3
{
    class Program
    {
        static void Main(string[] args)
        {
            
            string s = "例如：http://www.asd.com";
            Regex re = new Regex(@"(?<url>http(s)?://([\w-]+\.)+[\w-]+(/[\w- ./?%&=]*)?)");
            MatchCollection mc = re.Matches(s);
            foreach (Match m in mc)
            {
                s=s.Replace(m.Result("${url}"), String.Format("<a href='{0}'>{0}</a>", m.Result("${url}")));
            }
            Console.WriteLine(s);
        }
    }
}
//csharp/5524