Type not exposed by WCF Service

Question

Hello all,

I have a small test web service to emulate something odd I'm noticing in a real world app. As the demo shows the same behaviour as the app I will use the demo for brevity.

In short My service interface file looks as follows (as you can see it is the default WCF service created by VS2008 but I have added a new public method (GetOtherType()) and two new classes at the bottom (SomeOtherType and SomeComplexType). SomeOtherType manages a generic List of type SomeComplexType

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;

namespace WCFServiceTest
{

    [ServiceContract]
    public interface IService1
    {
        [OperationContract]
        string GetData(int value);

        [OperationContract]
        CompositeType GetDataUsingDataContract(CompositeType composite);

        [OperationContract]
        SomeOtherType GetOtherType();

    }


    [DataContract]
    public class CompositeType
    {
        bool boolValue = true;
        string stringValue = "Hello ";

        [DataMember]
        public bool BoolValue
        {
            get { return boolValue; }
            set { boolValue = value; }
        }

        [DataMember]
        public string StringValue
        {
            get { return stringValue; }
            set { stringValue = value; }
        }
    }

    [DataContract]
    public class SomeOtherType
    {
        public List<SomeComplexType> Items { get; set; }    
    }

    [DataContract]
    public class SomeComplexType
    {

    }
}

My Service is implemented as follows

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;

namespace WCFServiceTest
{

    public class Service1 : IService1
    {


        #region IService1 Members

        public string GetData(int value)
        {
            throw new NotImplementedException();
        }

        public CompositeType GetDataUsingDataContract(CompositeType composite)
        {
            throw new NotImplementedException();
        }

        #endregion

        #region IService1 Members


        public SomeOtherType GetOtherType()
        {
            throw new NotImplementedException();
        }

        #endregion
    }
}

The problem I have is that if I include a service reference to this service in an ASP.NET Web Application, I cannot see SomeComplexType via intellisense. The error relates to the type or namespace cannot be found. However, SomeOtherType can be found (I'm assuming as the type is a return type from one of the public methods).

Am I right in thinking I can't expose a type from a WCF Service if that type is not featured in the method signature of one of my public methods (either return type or argument)? If so, how would I be able to iterate over the Items inside an instance of SomeOtherType on the client?

Many Thanks and I hope this is clear.

Simon

Answer 1

I'm not at all an expert on this topic, so just as a shot in the blue: Empty DataContracts are discarded by WCF? Try exposing anything in ComplexDataType (some int is enough) and see if that changes anything.

Also, I believe you can verify the availability of the type using the built-in wcftestclient (you need to turn metadata exchange on for this).

Answer 2

Looks like you need the [DataMember] attribute on your SomeOtherType.Items property, i.e.

[DataMember]
public List<SomeComplexType> Items { get; set; }  

Answer 3

The problem I have is that if I include a service reference to this service in an ASP.NET Web Application, I cannot see SomeComplexType via intellisense. The error relates to the type or namespace cannot be found. However, SomeOtherType can be found (I'm assuming as the type is a return type from one of the public methods).

Am I right in thinking I can't expose a type from a WCF Service if that type is not featured in the method signature of one of my public methods (either return type or argument)? If so, how would I be able to iterate over the Items inside an instance of SomeOtherType on the client?

You are absolutely right - your SomeComplexType is never used in any of the service methods, and it's also never tagged as a [DataMember] in any of the types that are indeed used as parameters in your service methods. Therefore, from the point of view of WCF, it's not needed, and won't show up in the WSDL/XSD for the service.

As Graham already pointed out - you are using the SomeComplexType in one place:

[DataContract]
public class SomeOtherType
{
    public List<SomeComplexType> Items { get; set; }    
}

but since the Items element is not tagged as a [DataMember], it (and therefore the type it uses) will not be included in the WSDL/XSD of your service. Since the Items are not marked as DataMember, they won't be in your serialized WCF message either, so you won't ever need to iterate over this collection :-)

So most likely, what you really want, is just add the [DataMember] attribute to your Items property; then it'll be included in the WSDL/XSD, and so will the SomeComplexType.