Question

When building a WCF service for a large scale application, which is better:

In both cases, assume that the business logic layer is separated into a different assembly.

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Using your business logic layer as a service implementation i.e. with no code behind and no wrapper

<%@ ServiceHost Language="CS" Service="MyApp.BusinessLogic.BusLogicImpl" %>

or

Using the codebehind of the WCF service that wraps calls into your business logic layer.

<%@ ServiceHost Language="CS" Service="MyApp.WebServiceHost.Service" CodeBehind="Service.svc.cs" %>

Answer 1

If you need to have code behind your service, I would also put that into a separate assembly and store it in the .\bin directory of your ASP.NET website hosting the SVC file – I would never put that directly into a MyService.svc.cs code-behind file.

So you would have something like:

<%@ ServiceHost Language="CS" Service="MyApp.ServiceLayer.MyService" %>

and put all the logic and wrapper code you need (to call your business layer) into that assembly.