Can I prevent a StreamReader from locking a text file whilst it is in use?

Question

The StreamReader locks a text file whilst it is reading it.
Can I force the StreamReader to work in a "read-only" or "non locking" mode?

My workaround would be to copy the file to a temp location and read it from there but I would prefer to use the StreamReader directly if possible. Any alternative suggetions?

Background:
I've written a small app to get some stats out of a log file. This file is constantly being updating (several times a second) by an outside program lets call AAXXYY.

Reviewing the output suggests that my app may be locking the file and preventing AAXXYY from writing.

This is what I'm doing

    private void btnGetStats_Click(object sender, EventArgs e)     {         int countStarts = 0;         int countEnds = 0;          IList<string> sessions = new List<string>();          using(StreamReader stRead = new StreamReader(openFileDialog1.FileName,Encoding.Unicode))         {             while(!stRead.EndOfStream)             {                 string line = stRead.ReadLine();                 if(line.Contains("Session start"))                 {                     countStarts++;                     sessions.Add(line.Substring(line.IndexOf("["), line.LastIndexOf("]") - line.IndexOf("[")));                 }                 if (line.Contains("Session end"))                 {                     countEnds++;                     sessions.Remove(line.Substring(line.IndexOf("["), line.LastIndexOf("]") - line.IndexOf("[")));                 }             }         }          txtStarts.Text = countStarts.ToString();         txtEnds.Text = countEnds.ToString();         txtDifference.Text = (countStarts - countEnds).ToString();          listBox1.DataSource = sessions;     } 

Answer 1

You can pass a FileStream to the StreamReader, and create the FileStream with the proper FileShare value. For instance:

using (var file = new FileStream (openFileDialog1.FileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)) using (var reader = new StreamReader (file, Encoding.Unicode)) { }