C# – Mirroring console output to a file


In a C# console application, is there a smart way to have console output mirrored to a text file?

Currently I am just passing the same string to both Console.WriteLine and InstanceOfStreamWriter.WriteLine in a log method.

Best Solution

This may be some kind of more work, but I would go the other way round.

Instantiate a TraceListener for the console and one for the log file; thereafter use Trace.Write statements in your code instead of Console.Write. It becomes easier afterwards to remove the log, or the console output, or to attach another logging mechanism.

static void Main(string[] args)

    TextWriterTraceListener twtl = new TextWriterTraceListener(Path.Combine(Path.GetTempPath(), AppDomain.CurrentDomain.FriendlyName));
    twtl.Name = "TextLogger";
    twtl.TraceOutputOptions = TraceOptions.ThreadId | TraceOptions.DateTime;

    ConsoleTraceListener ctl = new ConsoleTraceListener(false);
    ctl.TraceOutputOptions = TraceOptions.DateTime;

    Trace.AutoFlush = true;

    Trace.WriteLine("The first line to be in the logfile and on the console.");

As far as I can recall, you can define the listeners in the application configuration making it possible to activate or deactivate the logging without touching the build.