Tim Van Wassenhove home

I couple of weeks ago i got a copy of Programming .NET Components… I can only suggest to read it yourself because i found it really good 😉 Anyway, in one of the chapters Juval Lowy talks about context and interception (msdnmag article). I got inspired and implemented my own log4net LoggingSink

public class LoggingSink : IMessageSink
{
	...

	public IMessage SyncProcessMessage(IMessage msg)
	{
		IMethodMessage methodMessage = msg as IMethodMessage;
		ILog log = LogManager.GetLogger(methodMessage.TypeName);
		log.Debug(methodMessage);

		IMessage message = this.nextSink.SyncProcessMessage(msg);

		IMethodReturnMessage methodReturnMessage = message as IMethodReturnMessage;
		if (methodReturnMessage != null)
		{
			log.Debug(methodReturnMessage);
		}

		return message;
	}
}

I also implemented my own MethodMessageRenderer and MethodReturnMessageRenderer using an ObjectRenderer that was inspired on the ObjectDumper that comes with the LINQ CTP samples

public class MethodReturnMessageRenderer : IObjectRenderer
{
	public MethodReturnMessageRenderer()
	{
	}

	public void RenderObject(RendererMap rendererMap, object obj, TextWriter writer)
	{
		IMethodReturnMessage methodReturnMessage = obj as IMethodReturnMessage;
		writer.WriteLine("{0}Called: {1}{2}Params:", Environment.NewLine, methodReturnMessage.MethodName, Environment.NewLine);
		ObjectRenderer.RenderObject(methodReturnMessage.Args, writer);
		if (methodReturnMessage.MethodName != ".ctor")
		{
			writer.WriteLine("{0}ReturnValue:", Environment.NewLine);
			ObjectRenderer.RenderObject(methodReturnMessage.ReturnValue, writer);
		}
		if (methodReturnMessage.Exception != null)
		{
			writer.WriteLine("{0}Exception:", Environment.NewLine);
			ObjectRenderer.RenderObject(methodReturnMessage.Exception, writer);
		}
		writer.WriteLine();
	}
}

Adding an [assembly: XmlConfigurator(Watch = true)] attribute to the AssemblyInfo.cs of projects that use log4Net seems the easiest way to get the configuration right. In your configuration you still have to register the IObjectRenderers

<renderer renderingClass="EndPointTools.MethodReturnMessageRenderer, EndPointTools" renderedClass="System.Runtime.Remoting.Messaging.IMethodReturnMessage, mscorlib"/>

Have a look at the generated log and feel free to download the complete solution: ContextBoundSamples.zip.