Problem consuming WF Service hosted in IIS from Silverlight Client

Question

I'm trying to consume a WF Service hosted in IIS express (xamlx) from a Silverlight Client.

I added my service reference and when I use the client proxy, I get this:

System.ServiceModel.CommunicationException was unhandled by user code
  Message=An error occurred while trying to make a request to URI 'http://localhost:52878/Workflows/PerformanceAppraisal/Exempt.xamlx'. This could be due to attempting to access a service in a cross-domain way without a proper cross-domain policy in place, or a policy that is unsuitable for SOAP services. You may need to contact the owner of the service to publish a cross-domain policy file and to ensure it allows SOAP-related HTTP headers to be sent. This error may also be caused by using internal types in the web service proxy without using the InternalsVisibleToAttribute attribute. Please see the inner exception for more details.
  StackTrace:
       at System.ServiceModel.AsyncResult.End[TAsyncResult](IAsyncResult result)
       at System.ServiceModel.Channels.ServiceChannel.EndCall(String action, Object[] outs, IAsyncResult result)
       at System.ServiceModel.ClientBase`1.ChannelBase`1.EndInvoke(String methodName, Object[] args, IAsyncResult result)
       at CompanyHR.ExemptPAService.ExemptPAClient.ExemptPAClientChannel.EndInitiatePerformanceAppraisal(IAsyncResult result)
       at CompanyHR.ExemptPAService.ExemptPAClient.CompanyHR.ExemptPAService.IExemptPA.EndInitiatePerformanceAppraisal(IAsyncResult result)
       at CompanyHR.ExemptPAService.ExemptPAClient.OnEndInitiatePerformanceAppraisal(IAsyncResult result)
       at System.ServiceModel.ClientBase`1.OnAsyncCallCompleted(IAsyncResult result)
  InnerException: System.Security.SecurityException
       Message=""
       StackTrace:
            at System.Net.Browser.AsyncHelper.BeginOnUI(SendOrPostCallback beginMethod, Object state)
            at System.Net.Browser.BrowserHttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
            at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelAsyncRequest.CompleteGetResponse(IAsyncResult result)
       InnerException: System.Security.SecurityException
            Message=Security error.
            StackTrace:
                 at System.Net.Browser.BrowserHttpWebRequest.InternalEndGetResponse(IAsyncResult asyncResult)
                 at System.Net.Browser.BrowserHttpWebRequest.<>c__DisplayClass5.<EndGetResponse>b__4(Object sendState)
                 at System.Net.Browser.AsyncHelper.<>c__DisplayClass4.<BeginOnUI>b__1(Object sendState)
            InnerException: 

When I added the service reference I didn't use http://localhost:52878/Workflows/PerformanceAppraisal/Exempt.xamlx

I used the https version of that. But it seems to be using this url instead.

I am using IIS Express in visual studio 2010.

Answer 1

The error message is quite clear about not being able to find a clientaccesspolicy.xml. This is the result of calling a service on a different site then the Silverlight app is running. You didn't mention the URL to the Silverlight app but it could either be the case of that using HTTPS or being a different site altogether.