I am trying to access specific area in text.how can I do this?

sw.WriteLine(1);

11:05:2018 __ 17:27:59 __ 01342 __ __25__ __ 720__
11:05:2018 __ 17:27:59 __ 09284 __ __28__ __ 729__
11:05:2018 __ 17:28:29 __ 01342 __ __25__ __ 720__

These are in text.So They are information about material's feature .Costumer can would like to know these features between dates.So on the interface there are two object that costumer should write dates and these information between dates will be written in listview.

private void Write_File()
       {
           string now = DateTime.Now.ToString("dd:MM:yyyy __ HH:mm:ss");

           sw = File.AppendText(filePath);


           sw.Write(now);
           sw.Write(" __ 01342 __");
           sw.Write(" __25__");
           sw.WriteLine(" __ 720__");


           sw.Write(now);
           sw.Write(" __ 09284 __");
           sw.Write(" __28__");
           sw.WriteLine(" __ 729__");

           sw.Flush();
           sw.Close();
       }