Generic Service Interface

Question

I have a Generic Service Interface:

[ServiceContract]
public interface IService<T> where T : Class1
{
    [OperationContract]
    void DoWork(T class1);
}

Then I have a Concrete Service that inherits from that:

public class Service : IService<Class1>
{
    public void DoWork(Class1 class1)
    {
    }
}

Everything works fine until I add a webHttpEndpoint to expose a JSON WS:

<service name="Service">
    <endpoint 
        address="" 
        binding="webHttpBinding" 
        behaviorConfiguration="webHttpBehavior"
        contract="IService"  />
</service>

<behavior name="webHttpBehavior">
    <enableWebScript />
</behavior>

In fact, I receive this error:

The contract name 'IService' could not be found in the list of contracts implemented by the service 'Service'.

That's beacuse of the generic definition of the interface. Any solution?

Well, your `Service` **doesn't** implement `IService` (as the error clearly says) - it implements `IService` - that's a different interface.... — marc_s, Jun 03 '11 at 07:11
You can try to use `contract="IService"` but I am afraid this won't work. WCF is not really well suited to generics..... — marc_s, Jun 03 '11 at 07:29

score 3 · Answer 1 · edited May 23 '17 at 12:22

3

In my opinion (and based on what you said), the interface does not need to be generic. The caller just need to know that there is a DoWork operation.

So basically, change the concrete class to be generic instead of the interface.

public class Service<T> : IService where T : Class1
{
    public void DoWork()
    {
    }
}

EDIT after clarifying the question: You need to provide the generic parameter in the config file as well:

contract="YourAssembly.IService`1[[YourAssembly.Class1, YourAssembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]"

Here is a similar question: Inheriting from a generic contract in WCF

edited May 23 '17 at 12:22

Community

1
1

answered Jun 03 '11 at 07:04

Johann Blais

9,389
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Thanks again. My contract looks like this now: contract="WebApplication1.IService`1[[WebApplication1.Class1, WebApplication1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]" but it does not work. – user758977 Jun 03 '11 at 09:51

score 2 · Answer 2 · answered Jun 03 '11 at 07:53

You must correctly write the type name of your contract into configuration. IService is not the name of IService<Class1>!!!

The configuration should look like:

<service name="Service">
    <endpoint 
        address="" 
        binding="webHttpBinding" 
        behaviorConfiguration="webHttpBehavior"
        contract="IService`1[Class1]"  />
</service>

<behavior name="webHttpBehavior">
    <enableWebScript />
</behavior>

Be aware that if your contract or service lives in any namespace, namespaces should be included in configuration.

Or in case of full names needed:

<service name="Namespace.Service, AssemblyName">
    <endpoint 
        address="" 
        binding="webHttpBinding" 
        behaviorConfiguration="webHttpBehavior"
        contract="Namespace.IService`1[[Namespace.Class1, AssemblyName]], AssemblyName"  />
</service>

<behavior name="webHttpBehavior">
    <enableWebScript />
</behavior>

Thanks for the answer. Same error. Can you give me a real example? — user758977, Jun 03 '11 at 11:27
The full type name also did not work for me, still WCF cannot find the contract. — AndiDog, Jan 22 '12 at 19:50

score 0 · Answer 3 · answered Jun 03 '11 at 06:55

Where is your Class1.....Instead of specifying any specific class make it a reference type using class

Try something this...

 [ServiceContract]public interface IService<T> where T : class
    { 
       [OperationContract] 
       void DoWork();
    }

Generic Service Interface

3 Answers3

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