C# Academy · Lesson

Logging abstractions, Debug/Trace

Use System.Diagnostics Debug/Trace, add listeners, and create a tiny ILogger-style abstraction to decouple app code from sinks.

Why logging

Aim:

Send messages with Debug and Trace
Add listeners to see output
Introduce a tiny logging abstraction
Pick levels and simple formatting

Debug/Trace basics

Debug is for development; Trace is for any build. Add a ConsoleTraceListener to see messages in console apps.

using System;
using System.Diagnostics;

// Demo: show Debug/Trace after adding a ConsoleTraceListener
public class Program
{
  public static void Main(string[] args)
  {
    // By default, console apps may not show Debug/Trace. Add a listener.
    Trace.Listeners.Clear();
    Trace.Listeners.Add(new ConsoleTraceListener());

    Debug.WriteLine("Debug: only in debug builds (often)");
    Trace.WriteLine("Trace: in all builds (commonly)");

    Trace.TraceInformation("Info message");
    Trace.TraceWarning("Warning message");
    Trace.TraceError("Error message");
  }
}

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