IsAnagram.cs

public static bool IsAnagram(string s, string t)
{
  if (s.Length != t.Length)
      return false;
  var s_hash = new Hashtable();
  var t_hash = new Hashtable();
  for (var i = 0; i < s.Length; i++)
  {
      s_hash[s.Substring(i, 1)] = 1 + 
                      (int)(s_hash.ContainsKey(s.Substring(i, 1)) ? 
                      s_hash[s.Substring(i, 1)] : 0);
      t_hash[t.Substring(i, 1)] = 1 + 
                      (int)(t_hash.ContainsKey(t.Substring(i, 1)) ? 
                      t_hash[t.Substring(i, 1)] : 0);
  }

  foreach (DictionaryEntry d in s_hash)
  {
      if (!t_hash.ContainsKey(d.Key))
          return false;
      else
          if ((int)d.Value != (int)t_hash[d.Key])
          return false;
  }
  return true;
}