public override bool ValidateUser(string username, string password)
{
   if (String.IsNullOrEmpty(username) || String.IsNullOrEmpty(password))
   {
      return false;
   }

   try
   {
      ReadUserFile();

      MembershipUser mu;

      if (_MyUsers.TryGetValue(username.ToLower(), out mu))
      {
         if (mu.Comment == password)
         {
            return true;
         }
      }

      return false;
   }
   catch (Exception ex)
   {
      throw new Exception(ex.Message.ToString());
   }
}
