Silverlight: Update service reference for a WCF service generating empty class

My Visual Studio sometimes goes angry. I had a Silverlight 2 – WCF – LINQToSQL application that I recently converted to Silverlight 3. I noticed that sometimes the Update Service Reference does not function properly and instead blanks out the generated reference.cs. It broke once again today and I decided to blog it. Here are the contents of Error window when such abnormal activity happens:

Custom tool error: Failed to generate code for the service reference '..'.  Please check other error and warning messages for details.


The warning tab may have many warnings, some of which are:

Custom tool warning: Unable to load one or more of the requested types. Retrieve the LoaderExceptions property for more information.

Custom tool warning: The type 'System.Collections.ObjectModel.ObservableCollection`1' could not be found.  Ensure that the assembly containing the type is referenced.  If the assembly is part of the current development project, ensure that the project has been built.

Custom tool warning: Cannot import wsdl:portType
Detail: An exception was thrown while running a WSDL import extension: System.ServiceModel.Description.DataContractSerializerMessageContractImporter
Error: Exception has been thrown by the target of an invocation.
XPath to Error Source: //wsdl:definitions[@targetNamespace='']/wsdl:portType[@name=..]

Custom tool warning: Cannot import wsdl:port
Detail: There was an error importing a wsdl:binding that the wsdl:port is dependent on.
XPath to wsdl:binding: //wsdl:definitions[@targetNamespace='..']/wsdl:binding[@name='..']

Custom tool warning: No endpoints compatible with Silverlight 3 were found. The generated client class will not be usable unless endpoint information is provided via the constructor.

Ok. Looks like something is wrong with the Observable Collection reference. This was further confirmed when I brought up the service configuration window (by right clicking the WCF service and selecting Configure Service Reference), and noticed that the ObservableCollection collection type has been replaced by { Custom } :

For comparison, here’s the normal screenshot for this window:

To get rid of this and regenerate service proxy properly, I had to remove the Reuse types in all referenced assemblies (or at least System assembly).

So, if such behavior ever happen to you, try to update the service reference after unchecking the reuse types checkbox. Once done, you can recheck the option and update your service reference again.

Silverlight-enabled WCF Service template

Before Beta 2 of silverlight 2, we needed some tweaks with the standard WCF service template to use it in our silverlight application. But luckily, the new Silverlight-enabled WCF Service template does the job lot easier for us. Now we just need to define our methods(marked with OperationContract atribute) in the service.svc.cs file and we are ready to consume it. No need to change the binding configuration to basicHttpBinding, no need to add ASP.NET compatibility support in special cases, no need to define method signatures in a separate contract file. Just use the new template and use the service in your silverlight application without any worries.