Regex reg = new Regex(@"([^/]*)(.aspx)", RegexOptions.IgnoreCase);
Match m = reg.Match(RawUrl);
if (m.Success)
{
    RawUrl = "/View.aspx?Code=" + m.Groups[1].Value;
    isMatch = true;
}

string result = Regex.Replace(yourStr, @"/([^/.]+)\.aspx(\?)?", delegate(Match m){if(m.Groups[2].Value == "") return "/View.aspx?Code="+m.Groups[1].Value; return "/View.aspx?Code="+m.Groups[1].Value+"&";}, RegexOptions.IgnoreCase);
richTextBox2.Text = result;

------解决方案--------------------

C# code
using System;
using System.Text.RegularExpressions;

class Program
{
  static void Main()
  {
    foreach (string s in new string[]{"/A0021.aspx","/A0021.ASPX?Name=zhang&Year=2008"})
    {
      string t = Convert(s);
      Console.WriteLine("{0} -> {1}", s, t);
    }
  }
  
  static string Convert(string s)
  {
    return Regex.Replace
    (
      s,
      @"(?i)/([^/]*).aspx(\?)?",
      delegate (Match m)
      {
        if (m.Value.EndsWith("?")) return "/View.aspx?Code=" + m.Groups[1].Value + "&";
        return "/View.aspx?Code=" + m.Groups[1].Value;
      }
    );
  }
}
/* 程序输出：
/A0021.aspx -> /View.aspx?Code=A0021
/A0021.ASPX?Name=zhang&Year=2008 -> /View.aspx?Code=A0021&Name=zhang&Year=2008
*/