Can you use interfaces as DataMembers in WCF?

Question

Can you do this?

[DataContract]
public class RegisterEndpointRequest : NotificationRegistrationServiceRequest
{
    [DataMember]
    public IEndpoint Endpoint { get; set; }
}

Notice the member Endpoint is an interface (IEndpoint), not a class. Will WCF allow this?

I *think* it will, as long as whatever concrete `IEndpoint` implementation you have for your `Endpoint` property is also decorated with a `DataContractAttribute` and appropriate `DataMemberAttribute`s on its members. **EDIT**: Plus what [Aasmund said](http://stackoverflow.com/a/11800139/74757) about the `KnownTypeAttribute`s. — Cᴏʀʏ, Aug 03 '12 at 16:59

score 8 · Answer 1 · answered Aug 03 '12 at 17:02

I think you can (but I haven't tested it), but you will then need to declare all implementations of that interface with [KnownType]:

[DataContract]
[KnownType(typeof(EndpointImplA))]
[KnownType(typeof(EndpointImplB))]
public class RegisterEndpointRequest : NotificationRegistrationServiceRequest
{
    [DataMember]
    public IEndpoint Endpoint { get; set; }
}

Each implementing class must have a [DataContract] attribute.

score 3 · Accepted Answer · edited May 23 '17 at 12:17

3

The DataContractAttribute in WCF is not intended for use on an interface: See the documentation here

The answer in this question may give you a better idea why.

edited May 23 '17 at 12:17

Community

1
1

answered Aug 03 '12 at 16:55

chridam

100,957
23
236
235

1

He's applying `[DataContract]` to a class, and `[DataMember]` to a property. – Aasmund Eldhuset Aug 03 '12 at 17:00

score 1 · Answer 3 · answered Sep 24 '15 at 06:48

Yes, of course you can have interface as DataMember inside DataContract.. Then you have to have specify all the interface implementations in the KnownType attributes...

 [DataContract]
    [KnownType(typeof(ActivityDC))]
    [KnownType(typeof(StepDC))]
    [KnownType(typeof(WaveDC))]
    public class CampaignDC : AuditedEntityBaseDC
    {
        [DataMember]
        public IList<IActivityDC> Activities { get; set; }

Can you use interfaces as DataMembers in WCF?

3 Answers3