try
             {

               XmlDocument xmldoc = new XmlDocument();
               XmlReader reader = new XmlTextReader(Stream.Null);//Stream
               reader.MoveToContent();
               reader.ReadToFollowing("cNF");
               reader.Read();
               return reader.Value;

            if (_NFE_CHAVE_ACESSO.getNFEChaveAcesso(reader.Value) == null)
            {
                var XML = _NFE_CHAVE_ACESSO.getNFEChaveAcesso(reader.Value,
               );
            }

        }
        catch
        {
            return "";
        }
    }