Question

I have a WCF service with a private constructor. If I’m not wrong, constructors must be parameterless in WCF and the parameter I need is the caller’s name (or caller’s method name), so I can assign a few readonly fields.

Is there a way that I can get the caller’s name — or the method that invoked it? I was playing around with OperationContext.Current, but without any luck.

Answer 1

I wouldn’t recommend accessing the stack trace for performance reasons.

WCF service constructors only need to be parameterless if you are using the default ServiceHostFactory. You can specify a custom service factory in your .svc file like this:

<%@ ServiceHost Language="C#" Debug="true"
   Service="Namespace.To.Service"
   Factory="Namespace.To.ServiceFactory" %>

The process to creating your class in a custom way goes like this:

1. Your ServiceHostFactory creates an instance of your custom ServiceHost in CreateServiceHost
2. ServiceHost overrides OnOpening and adds a custom IServiceBehavior to Description.Behaviors (Description is a property on the base class)
3. Your IServiceBehavior implements ApplyDispatchBehavior and enumerates serviceHostBase.ChannelDispatchers, checking if each is a ChannelDispatcher.
   • Each ChannelDispatcher’s Endpoints property is enumerated and it’s DispatchRuntime.InstanceProvider is changed to a custom IInstanceProvider
4. The custom IInstanceProvider creates the instance in GetInstance

I have used this to delegate creation to an IoC container.