WC Data Services 5.6.0 - Request Error

Question

I created an empty asp.net project, download the following package:

Microsoft.OData.EntityFrameworkProvider –Pre

So I get WCF Data Services 5.6.0 and support for Entity Framework 6.0. All references are added successfully to the project.

Then I add a new ado.net entity model and generate just one entity from the database. I then add a WCF data service with the following code:

#if DEBUG
    [ServiceBehavior(IncludeExceptionDetailInFaults = true)]
#endif
    public class MyService : DataService<MyContext>
    {
        public static void InitializeService(DataServiceConfiguration config)
        {
        #if DEBUG
            config.UseVerboseErrors = true;
        #endif

            config.SetEntitySetAccessRule("*", EntitySetRights.All);
           config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V3;
        }
    }

But when I view the service in the IE, I get the following error:

The server encountered an error processing the request. The exception message is 'Expression of type 'System.Data.Entity.Core.Objects.ObjectContext' cannot be used for return type 'System.Data.Objects.ObjectContext''. See server logs for more details. The exception stack trace is:

at System.Linq.Expressions.Expression.ValidateLambdaArgs(Type delegateType, Expression& body, ReadOnlyCollection1 parameters) at System.Linq.Expressions.Expression.Lambda[TDelegate](Expression body, String name, Boolean tailCall, IEnumerable1 parameters) at System.Data.Services.Providers.DbContextHelper.CreateDbContextAccessor(Type type) at System.Data.Services.Providers.DbContextHelper.GetDbContextAccessor(Type type) at System.Data.Services.DataService1.CreateMetadataAndQueryProviders(IDataServiceMetadataProvider& metadataProviderInstance, IDataServiceQueryProvider& queryProviderInstance, Object& dataSourceInstance, Boolean& isInternallyCreatedProvider) at System.Data.Services.DataService1.CreateProvider() at System.Data.Services.DataService1.HandleRequest() at System.Data.Services.DataService1.ProcessRequestForMessage(Stream messageBody) at SyncInvokeProcessRequestForMessage(Object , Object[] , Object[] ) at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs) at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage41(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage3(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage1(MessageRpc& rpc) at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)

Am I missing something else?

Seems that you're using a wrong class here. ObjectContext exists in two namespaces. Check that. — Saeed Neamati

Ivan-Mark Debono Ivan-Mark Debono · Accepted Answer · 2013-11-13T09:55:51

Problem solved. One must add the following to the service:

using System.Data.Services.Providers;

and change the base class to:

public class MyService : EntityFrameworkDataService<MyContext>

WC Data Services 5.6.0 - Request Error

1 Answers