WCF: Interfaces, Generics and ServiceKnownType

Question

I have the following:

[ServiceContract]
[ServiceKnownType(typeof(ActionParameters))]
[ServiceKnownType(typeof(SportProgram))]
[ServiceKnownType(typeof(Action         


        

Answer 1

It's an old question and even though the accepted answer is totally correct, I stumpled upon this in the search for a similiar problem and thought I could share my experiences. It's often a headache, but it is possible to use generics combined with interfaces with WCF. Here's a working example of another (similiar) implementation that I've done:

[ServiceContract]
[ServiceKnownType(typeof(CollectionWrapper))]
public interface IService : 
{
    [OperationContract]
    ICollectionWrapper FindAssociation(string name, int pageSize, int page);
}

public interface ICollectionWrapper
{
    int TotalCount { get; set; }
    IEnumerable Items { get; set; }
}

[KnownType(typeof(OrganizationDto))]
[KnownType(typeof(CompanyDto))]
public class CollectionWrapper : ICollectionWrapper
{
    [DataMember]
    public int TotalCount { get; set; }
    [DataMember]
    public IEnumerable Items { get; set; }
}

public class CompanyDto :  IAssociation
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class OrganizationDto :  IAssociation
{
    public int Id { get; set; }
    public string Name { get; set; }
}

The key here is to use the combination of KnownType and ServiceKnownType.

So in your case you can do something like this:

[ServiceContract]
[ServiceKnownType(typeof(ActionParameters))]
[ServiceKnownType(typeof(ActionResult))] // Actual implementation of container, but interface of generic.
public interface ISportProgramBl  
{
    [OperationContract]
    IActionResult Get(IActionParameters parameters);
}

[KnownType(typeof(SportProgram))] // Actual implementation here.
public class ActionResult
{
    // Other stuff here
    T FooModel { get; set; }
}

This will work if you have a shared contract (access to the actual service interface) and consume the contract with ChannelFactory. I do not know if it works with a service-reference.

However, there seems to be some issues with the implementation as mentioned here:

WCF With a interface and a generic model

And another similiar question asked and answered here:

Generic return types with interface type params in WCF