如何从所有xml文件目录和子目录中搜索txtnumber

Question

如何从所有xml文件中搜索txtnumber并获取包含数字的文件。搜索所有目录和子目录。仅显示dateTimeStr等于和大于directorylast修改日期

   var dateTimeStr = "11/04/2016 12:31";
            var user_time = DateTime.Parse(dateTimeStr);

            var dateTimeStr2 = "22/03/2016 16:34";
            var user_time2 = DateTime.Parse(dateTimeStr2);
            DirectoryInfo info = new DirectoryInfo(path);
            DataSet dss = null; 
            if (info.LastWriteTime >= user_time)
            {

                var allfiles = Directory.GetFiles(path, "*.xml", System.IO.SearchOption.AllDirectories);


                foreach (var item in allfiles)
                {
                    DateTime lastModified = System.IO.File.GetLastWriteTime(item);

                    //string extension;

                    //extension = Path.GetExtension(item);

                    if (lastModified.ToShortTimeString() == user_time2.ToShortTimeString())
                    {


                        XmlReader xmlFile;
                        xmlFile = XmlReader.Create(item, new XmlReaderSettings());
                       dss = new DataSet(); 
                        DataView dv;
                        dss.ReadXml(xmlFile);

                        string time = dss.Tables[0].Rows[0]["starttime"].ToString();
                        string number = dss.Tables["Party"].Rows[0]["number"].ToString();
                        time = time.Substring(0, 19);
                        var getxmldate = time;
                        var datetimecheck = DateTime.Parse(getxmldate);
                        if (datetimecheck.ToShortTimeString() == user_time2.ToShortTimeString() && number =="202")
                        {

                            string filename = dss.Tables["recording"].Rows[0]["filename"].ToString();
                            string pathwav = item.Replace(".xml", ".wav");
                            using (SoundPlayer player = new SoundPlayer(pathwav))
                            {
                                // Use PlaySync to load and then play the sound.
                                // ... The program will pause until the sound is complete.
                                player.PlaySync();
                            }
                          //  Process.Start(item + ".wav");
                        }

                    }                   


                }

            }