How do I properly set up a Silverlight-Enabled WCF Service?

Question

EDIT: I started a closed vote on this question because I resolved the issue. I was doing everything fine, but a reference to an ASP URL rewriter that I downloaded and uninstalled a while ago still had a reference in IIS. This forum post by Waclaw Stypula (the one with the steps) helped me track this down, by accident. When I launched the run command, IIS told me that it (obviously) could not find the rewriter DLL. I removed the reference and the app ran fine after that.

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I am following the silverlight.net tutorials by Jesse Liberty. Currently I am trying to do tutorial three, but I am running into a wall under the heading "CREATE THE WEB SERVICE" (about halfway down).

First, when I create the new service by adding it to the solution, the tutorial indicates that three files should be created; IService1.vb, Service1.svc, and Service1.svc.vb. I do not get the IService1.vb file when I add the service to the solution. I downloaded the copy of the project they provided, and the Service1.svc.vb file is in there, so I added one manually and copied the contents of the file. The tutorial says it is a VB tutorial, but displays C# in the accompanying screenshot so maybe that is the issue.

After I get all the files made up like the tutorials (copy/paste to make sure I don't have a typo), I try to add the service reference and get the following error:

The service class of type KeyboardControl_Web.Service1 both defines a ServiceContract and inherits a ServiceContract from type KeyboardControl_Web.IService1. Contract inheritance can only be used among interface types. If a class is marked with ServiceContractAttribute, it must be the only type in the hierarchy with ServiceContractAttribute. Consider moving the ServiceContractAttribute on type KeyboardControl_Web.IService1 to a separate interface that type KeyboardControl_Web.IService1 implements.

I tried googling different portions of the message, but did not find much useful information.

Here is the code for the different files:

//IService1.vb
Imports System.ServiceModel

' NOTE: If you change the class name "IService1" here, you must also update
'       the reference to "IService1" in Web.config.
<ServiceContract()> _
Public Interface IService1

    <OperationContract()> _
   Function GetAllLocations() As List(Of Address)

End Interface

//Service1.svc.vb
Imports Microsoft.VisualBasic
Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Runtime.Serialization
Imports System.ServiceModel
Imports System.Text

' NOTE: If you change the class name "Service1" here, you must also
'       update the reference to "Service1" in Web.config and in the
'       associated .svc file.

Public Class Service1
    Implements IService1
    Public Function GetAllLocations() As List(Of Address) Implements IService1.GetAllLocations
        Dim db As New DataClasses1DataContext()
        Dim matchingCustomers = From cust In db.userControlDemos Select cust
        'Return matchingCustomers.ToList()
    End Function
End Class

I am new to Silverlight/WCF in general, as well as to Interfaces and Services. Can you guys help me get on the right track?

EDIT: I should add that I am using Visual Studio 2008, on Windows Vista Business SP1.

Answer 1

Hi Anders, if you have the Silverlight Tools for Visual Studio installed, instead of using the default WCF template, consider using the "Silverlight-enabled WCF Service" which simplifies things for you and puts all the required configuration in place. This new template was introduced in Beta 2 and still exist (ref: http://timheuer.com/blog/archive/2008/06/06/changes-to-accessing-services-in-silverlight-2-beta-2.aspx).

Answer 2

Hi Anders, i have the same problem as you. so pls reply me if you get the solution.