Open the log gile to read while it is in use

Question

Hi All,
I have implemented log functionality in my application which keeps track of all the user activities from the moment the application starts and till user exits the application. In My Application I create an instance of StreamWriter when the application begins and closing Stream Writer when the application exits.
My questions is when my application is running , I want to be able to go to the log file (\\program files\\MyApplication\\log.txt") and check the log contents. When I try to pen the log file it throws an error "An error occured. The document could not be opened". How can I view the log file and see the contents when the application is running and writing to the log file?
===============================================================
StreamWriter SW; //global variable
 private void StartLogger()
 {
           
   string fPath = "\\Program Files\\My App\\log.txt;
   SW = File.CreateText(fPath );
                     
  //Write in to log file
   LogEntry("logfile created");
 }

private void LogEntry(string entry)
{
   SW.WriteLine(entry + "\n");
   SW.Flush();
}
Thanks,
Ram