Actually, the GUID thing is a behavior happens when a rolling trace listener instance has the exclusive write access on the file and another rolling trace listener tries to write on that same file. It is briefly explained on this
blog. Here is the code:
this.writer = new StreamWriter(fileNameWithPath, true, encoding1, 0x1000);
Guid guid1 = Guid.NewGuid();
fileName = guid1.ToString() + fileName;
fileNameWithPath = Path.Combine(folderPath, fileName );
The tracer is set to a category that points to a RollingFlatFileTraceListener (when you called the Tracer.StartTrace("CategoryName")) so the writing method is indeed on the trace listener. You can see it yourself if you step through the code.
Moving on to your question, I believe this can't be done easily since Tracer is per category basis. One work around I can think of is to use Fluent Configuration API to be able to modify the filename at runtime.
Noel Angelo Bolasoc
Global Technologies and Solutions