I have an Entity Framework data model. Part of the model is a Customer entity. The web service provides a method to get a customer, and to receive an updated version of this customer to be persisted.

To test this, I created a new ASP.NET web Application, (Solution > Add > New Project > ASP.NET Web Application), then added a reference to my service reference using the standard Add Service Reference dialog. I then call the service using the following code:

var client = new CustomerServiceClient();
var customer = client.GetCustomerByID(18); // get it
customer.LimitDown = 100; // change it
client.SaveCustomer(customer); // persist it

Everything works as expected.

Now, I do exactly the same thing, but this time with as ASP.NET Web Site (Solution > Add > New Web Site > ASP.NET Web Site). I add the reference in a similar fashion and copy and paste the code above into the new site. But now I get the following exception thrown on the 4th line:

System.InvalidOperationException The EntityReference object could not be serialized. This type of object cannot be serialized when the RelationshipManager belongs to an entity object that does not implement IEntityWithRelationships.

Source Error:

Line 2474: Line 2475:
public SkyWalkerCustomerService.OperationResult SaveCustomer(SkyWalkerCustomerService.Customer customer) { Line 2476:
return base.Channel.SaveCustomer(customer); Line 2477: } Line 2478: }

Stack Trace:

System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) +9475203
System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) +345
SkyWalkerCustomerService.ICustomerService.SaveCustomer(Customer customer) +0
SkyWalkerCustomerService.CustomerServiceClient.SaveCustomer(Customer customer) in c:\Windows\Microsoft.NET\Framework\v4.0.30128\Temporary ASP.NET Files\testsite2\dd2bcf8d\f95604ff\App_WebReferences.fz4h7x7l.0.cs:2476 _Default.Page_Load(Object sender, EventArgs e) in c:\Users\Mike\Documents\Repositories\UWC\SkyWalker\TestSite2\Default.aspx.cs:17 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
System.Web.UI.Control.OnLoad(EventArgs e) +91
System.Web.UI.Control.LoadRecursive() +61 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1966

Googling for this error returns very little. Why doesn't this work?