Have a look at System.Runtime.Remoting.Proxies.RealProxy. You can use this to create an instance that appears to be the target type from the perspective of the caller. RealProxy.Invoke provides a point from which you can simply invoke the target method on the underlying type or perform additional processing before/after the call (logging, for example).
Here’s an example of a proxy that logs to the console before/after each method invocation:
public class LoggingProxy<T> : RealProxy
{
private readonly T _instance;
private LoggingProxy(T instance)
: base(typeof(T))
{
_instance = instance;
}
public static T Create(T instance)
{
return (T)new LoggingProxy<T>(instance).GetTransparentProxy();
}
public override IMessage Invoke(IMessage msg)
{
var methodCall = (IMethodCallMessage)msg;
var method = (MethodInfo)methodCall.MethodBase;
try
{
Console.WriteLine("Before invoke: " + method.Name);
var result = method.Invoke(_instance, methodCall.InArgs);
Console.WriteLine("After invoke: " + method.Name);
return new ReturnMessage(result, null, 0, methodCall.LogicalCallContext, methodCall);
}
catch (Exception e)
{
Console.WriteLine("Exception: " + e);
if (e is TargetInvocationException && e.InnerException != null)
{
return new ReturnMessage(e.InnerException, msg as IMethodCallMessage);
}
return new ReturnMessage(e, msg as IMethodCallMessage);
}
}
}
Here is how you would use it:
IMyInterface intf = LoggingProxy<IMyInterface>.Create(new MyClass());
intf.MyProcedure();
The output to console would then be:
Before invoke: MyProcedure
Hello World
After invoke: MyProcedure