How Do I Reference a WCF Client from a WCF Service Without Changing the Latter's Binding?

Question

I have a C# WCF service and I need to reference another web service. The old service is written in Visual Basic and is not WCF.

The former is supposed to deprecate the latter, but there are some methods in the old service which are complex. Consequently, I would like to call the methods in the old service from the new service.

To avoid naming confusion I want to encapsulate the wrapper for the old services in a separate project, which is referenced from the new service. However, when I tried calling the wrapper from the new services project, the new service threw an InvalidSoapOperation. This exception is not thrown when I call the old services from the wrapper project itself.

Normally, I'd copy and paste the bindings for the old service from the wrapper project to the new project, but because of the similarity of the contracts, I am hesistant to do that.

Is there a way to "indirectly" reference the old service through the wrapper project, so that the new service project is not directly coupled the old service?

EDIT: The stack trace is as follows:

System.InvalidOperationException was unhandled by user code
  HResult=-2146233079
  Message=Could not find default endpoint element that references contract 'OldService.OldServiceSoap' in the ServiceModel client configuration section. This might be because no configuration file was found for your application, or because no endpoint element matching this contract could be found in the client element.
  Source=System.ServiceModel
  StackTrace:
       at System.ServiceModel.Description.ConfigLoader.LoadChannelBehaviors(ServiceEndpoint serviceEndpoint, String configurationName)
       at System.ServiceModel.ChannelFactory.ApplyConfiguration(String configurationName, Configuration configuration)
       at System.ServiceModel.ChannelFactory.ApplyConfiguration(String configurationName)
       at System.ServiceModel.ChannelFactory.InitializeEndpoint(String configurationName, EndpointAddress address)
       at System.ServiceModel.ChannelFactory`1..ctor(String endpointConfigurationName, EndpointAddress remoteAddress)
       at System.ServiceModel.ConfigurationEndpointTrait`1.CreateSimplexFactory()
       at System.ServiceModel.ConfigurationEndpointTrait`1.CreateChannelFactory()
       at System.ServiceModel.ClientBase`1.CreateChannelFactoryRef(EndpointTrait`1 endpointTrait)
       at System.ServiceModel.ClientBase`1.InitializeChannelFactoryRef()
       at System.ServiceModel.ClientBase`1..ctor()
       at OldServiceWrapper.OldService.OldServiceClient..ctor() in C:...\MyProject\Service References\TheOldService\Reference.cs:line 21614

The App.Config in the Wrapper Project:

<system.serviceModel>
        <bindings>
            <basicHttpBinding>
                <binding name="OldServiceSoap" />
            </basicHttpBinding>
        </bindings>
        <client>
            <endpoint address="http://localhost/OldService/OldService.asmx"
                binding="basicHttpBinding" bindingConfiguration="LogOrderSoap"
                contract="OldService.OldServiceSoap" name="OldServiceSoap"/>
        </client>
</system.serviceModel>

What was the content of the exception? This could just be a context issue where the user the code is running under doesn't have access to the outside world. — Justin Killen, Jul 02 '14 at 22:55
Posted working app.config for the wrapper and the stack trace. There is no mention of the old service in the new WCF service; all it has is a Visual Studio "reference" to the wrapper project. — S. Dixon, Jul 03 '14 at 15:12
If I could reference the client's App.Config from my Web.Config that might work. — S. Dixon, Jul 03 '14 at 15:15
I'm not sure how to access the App.Config, but I'm pretty sure you can just copy the contents of it into Web.Config — Justin Killen, Jul 03 '14 at 15:29

score 1 · Answer 1 · answered Jul 03 '14 at 15:27

1

The way you build your new service it is a client of your old service. Therefore you have to integrate the app.config of the wrapper into the web.config of the new service.

answered Jul 03 '14 at 15:27

Dirk Brockhaus

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What specifically would you do to integrate the two? – S. Dixon Jul 03 '14 at 15:33
Merge the two system.serviceModel sections. You need a configuration with client and service elements. – Dirk Brockhaus Jul 03 '14 at 15:36
I solved this by copying the binding and client elements from the app.config file above. No new service element was needing. – S. Dixon Jul 03 '14 at 18:25
That’s what I mean with the term „merge“. Sorry I have been too unclear :-) – Dirk Brockhaus Jul 04 '14 at 07:11

score 1 · Accepted Answer · edited May 23 '17 at 12:04

The solution is to copy and paste the binding and client information in the referenced project to that of the wrapper project.

As stated in C# DLL config file:

Whereas there is rarely a need to track settings separately for different copies of an app within one user profile, it's very unlikely that you would want all of the different usages of a DLL to share configuration with each other. For this reason, when you retrieve a Configuration object using the "normal" method, the object you get back is tied to the configuration of the App Domain you are executing in, rather than the particular assembly.

Or as Sam Holder put in Reference Web.Config file from another project in same solution C#:

class libraries do not have their own configuration. They use the configuration of which ever executable they are being used in.

In C#, the standard practice is that configuration should belong to the application, not the referenced DLL. Therefore, it makes sense to copy and paste the app.config information to the calling project. This does not require you to reference the old web service from the calling project directly, as I was worried that it would.

How Do I Reference a WCF Client from a WCF Service Without Changing the Latter's Binding?

2 Answers2