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));

score 2 · Accepted Answer · answered Mar 06 '14 at 20:18

2

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.

answered Mar 06 '14 at 20:18

Jon Peterson

723
7
21

I like the idea, but when specifying the type in the App.config `type=MyNamespace.MyTextWriterTraceListener` the program crashes. – Matthew Finlay Mar 06 '14 at 22:36
Interesting. I made a similar custom listener just the other day and had no problems. The one bit that I had to add into my app.config was `type="MyNamespace.MyTextWriterTraceListener, AssemblyNameContainingListener"`. Also make sure that the assembly containing it is being copied, I had a unit test that referenced it in the app.config but not in the code so Visual Studio was helpful enough to not copy it local. – Jon Peterson Mar 07 '14 at 16:25
Thanks, I was leaving off the assembly name. – Matthew Finlay Mar 10 '14 at 02:53

score 2 · Answer 2 · answered Feb 07 '12 at 05:30

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.

answered Feb 07 '12 at 05:30

jhsowter

619
3
8

3

-1 doesn't answer the question at all. OP wasn't asking for alternative logging solutions but rather how to configure the one chosen. – Jon Peterson Mar 06 '14 at 17:42
1

@JonPeterson I disagree. There is a reasonable chance that this answer will be helpful to somebody, somewhere. – Holf Dec 22 '16 at 12:42

score 0 · Answer 3 · answered Oct 23 '14 at 08:56

0

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.

answered Oct 23 '14 at 08:56

Markus

1

Thank you, but I was looking for a solution that would allow specification of the writer in config. Your solution is at the bottom of the question as the behaviour I would like to replicate :) – Matthew Finlay Oct 23 '14 at 09:38

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

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