S6670 — "Trace.Write" and "Trace.WriteLine" should not be used

Why is this an issue?

Trace.Write and Trace.WriteLine methods are writing to the underlying output stream directly, bypassing the trace formatting and filtering performed by TraceListener.TraceEvent implementations. It is preferred to use Trace.TraceError, Trace.TraceWarning, and Trace.TraceInformation methods instead because they call the TraceEvent method which filters the trace output according to the TraceEventType (Error, Warning or Information) and enhance the output with additional information.

How to fix it

Use the Trace.TraceError, Trace.TraceWarning, or Trace.TraceInformation methods.

Noncompliant code example

try
{
    var message = RetrieveMessage();
    Trace.Write($"Message received: {message}"); // Noncompliant
}
catch (Exception ex)
{
    Trace.WriteLine(ex); // Noncompliant
}

Compliant solution

try
{
    var message = RetrieveMessage();
    Trace.TraceInformation($"Message received: {message}");
}
catch (Exception ex)
{
    Trace.TraceError(ex);
}

Resources

Documentation

• Microsoft Learn - Trace.TraceError Method
• Microsoft Learn - Trace.TraceInformation Method
• Microsoft Learn - Trace.TraceWarning Method
• Microsoft Learn - Trace.Write Method
• Microsoft Learn - Trace.WriteLine Method
• Microsoft Learn - TraceListener.TraceEvent Method

Articles & blog posts

• Stackoverflow - Difference between Trace.Write() and Trace.TraceInformation()