How do you stop a TextWriterTraceListener from appending using app.config?

Question

I'm using System.Diagnostics.TraceSource for logging and one of my listeners is a TextWriterTraceListener. In the tracing primer here it sets this up as follows:

<listeners>
  <add initializeData="output.txt" 
       type="System.Diagnostics.TextWriterTraceListener"
       name="myLocalListener" />
</listeners>

The problem is that this will always append to output.txt. How do you alter this to an overwrite in the config file?

Programmatically the listener I want is a:

new TextWriterTraceListener(new StreamWriter("output.txt", false));

Answer 1

The simplest solution is to make your own.

I suggest that you inherit from TextWriterTraceListener and in your constructor set the base Writer to what you proposed: new StreamWriter("output.txt", false).

Some sample code:

public class MyTextWriterTraceListener : TextWriterTraceListener
{
    public MyTextWriterTraceListener(string logFileName)
        : base(logFileName)
    {
        base.Writer = new StreamWriter(logFileName, false);
    }
}

This lets you take the initializeData parameter from a configuration file to specify the name of the file, or specify one if created in code.

Answer 2

I know this doesn't directly answer your question, but use NLog instead. It does more stuff than out-of-the-box diagnostics in terms of logging options and it's really easy to use.

Answer 3

Even more simpler, just tell the TestWriterTraceListener to not append the file:

TextWriterTraceListener twtl = new TextWriterTraceListener(new StreamWriter(@"<path to my logfile>", false));

By selecting false the logfile is overwritten each time you initialize the TextWriterTraceListener.