How to: Disable/Enable WCF tracing in C# applicati

Question

It took me a while to get this right, so I decided to share a solution because it might save someone else several days of trial and error.

The problem: I want to be able to enable/disable WCF tracing in my C# .NET application and choose the trace output filename. I don't want users editing the .config file, there's too much room for error there.

Here is one solution.

The application's .config file:

<?xml version="1.0"?>
<configuration>
  <system.diagnostics>
    <trace autoflush="true"/>
    <sources>
      <source name="System.ServiceModel" switchValue="All">
        <listeners>
          <add name="MyListener"/>
        </listeners>
      </source>
      <source name="System.ServiceModel.MessageLogging" switchValue="All">
        <listeners>
          <add name="MyListener"/>
        </listeners>
      </source>
      <source name="System.ServiceModel.Activation" switchValue="All">
        <listeners>
          <add name="MyListener"/>
        </listeners>
      </source>
      <source name="System.IdentityModel" switchValue="All">
        <listeners>
          <add name="MyListener"/>
        </listeners>
      </source>
    </sources>
    <sharedListeners>
      <add name="MyListener" type="MyNamespace.MyXmlListener, MyAssembly"/>
    </sharedListeners>
  </system.diagnostics>
  <system.serviceModel>
    <diagnostics wmiProviderEnabled="true">
      <messageLogging
        logEntireMessage="true"
        logMalformedMessages="true"
        logMessagesAtServiceLevel="true"
        logMessagesAtTransportLevel="true"
        maxMessagesToLog="1000"
        maxSizeOfMessageToLog="8192"/>
    </diagnostics>
  </system.serviceModel>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
  </startup>
</configuration>

My C# code:

using System;
using System.IO;
using System.Diagnostics;
namespace MyNamespace
{
    public class MyXmlListener : XmlWriterTraceListener
    {
        public static String TraceOutputFilename = String.Empty;

        public static Stream MakeOutputStream()
        {
            if (String.IsNullOrWhiteSpace(TraceOutputFilename))
                return Stream.Null;

            return new FileStream(TraceOutputFilename, FileMode.Create);
        }

        public MyXmlListener ()
            : base(MakeOutputStream())
        { }
    }
}

To enable WCF tracing to a file, set TraceOutputFilename before the WCF object is created:

MyXmlListener.TraceOutputFilename = "trace.svclog";

I've gotten great benefits from this forum, I hope this post pays it forward!

See Specifying Fully Qualified Type Names for setting the "type" correctly in a .config file.