Using Workflow Extensions (context.GetExtension) in IIS-hosted workflows

Question

I must be missing something simple, but how is one supposed to set default extension providers for IIS hosted workflows (eg. XAMLX)?

I want to inject a service and use it in many activities like:

IFoo aFoo = context.GetExtension<IFoo>();

If I were hosting it myself I would have access to a WorkflowServiceHost and at startup would do something like:

host.WorkflowExtensions.Add<IFoo>(() => new FooImp());

but how would I set an IFoo for my XAMLX instances to use?

Thanks!

Answer 1

Basically you use an IServiceBehavior to add the extension and a BehaviorExtensionElement to add the IServiceBehavior.

 

public class StringWriterBehavior : IServiceBehavior
{
    public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase)
    {
        var host = (WorkflowServiceHost)serviceHostBase;
        host.WorkflowExtensions.Add<TextWriter>(() => new StringWriter());
    }
}

public class StringWriterElement : BehaviorExtensionElement
{
    public override Type BehaviorType
    {
        get { return typeof(StringWriterBehavior); }
    }

    protected override object CreateBehavior()
    {
        return new StringWriterBehavior();
    }
}

And the config file:

<system.serviceModel>
  <extensions>
    <behaviorExtensions>
      <add name=“stringWriter“
           type="OrderService.StringWriterElement, MyWorkflowService"/>
    </behaviorExtensions>
  </extensions>
  <services>
    <service name="OrderWorkflow“
             behaviorConfiguration="OrderWorkflowBehavior">
    </service>
  </services>
  <behaviors>
    <serviceBehaviors>
      <behavior name="OrderWorkflowBehavior">
        <serviceMetadata httpGetEnabled="True"/>
        <stringWriter />
      </behavior>
    </serviceBehaviors>
  </behaviors>
</system.serviceModel>

Maurice