Question

I have set the ThreadContext.Properties and need to update its value during the life-cycle of my code. In the past I have used log4j MDC and had to:
MDC.remove(TRACKING);

and then add another value by:
MDC.put(TRACKING, trackingIdStr);

Now that I am using Log4Net, our app uses Properties:
log4net.ThreadContext.Properties[“TrackingId”] = tracker;

Question: How do I remove the previous value and add a new value? Is it as easy as just:
log4net.ThreadContext.Properties[“TrackingId”] = tracker2;

Answer 1

Yes, it is that easy.  You can reassign as you have shown in your question or you can remove the value altogether when you are finished with it. 

//set
ThreadContext.Properties["TrackingId"] = tracker1;

//reset
ThreadContext.Properties["TrackingId"] = tracker2;

//completely remove
ThreadContext.Properties.Remove("TrackingId");

If you want your context properties to be in effect for a specific section of code (via using) then you can try ThreadContext.Stacks:

using(ThreadContext.Stacks["TrackingId"].Push("hello"))
{
  //messages logged here will be tagged with TrackingId="hello"
}
//messages logged here will not be tagged with TrackingId="hello"